diff --git a/.eslintrc b/.eslintrc
index d2147b4..e6dd07c 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -31,7 +31,7 @@
     },
     "extends": "eslint:recommended",
     "parserOptions": {
-        "ecmaVersion": 6,
+        "ecmaVersion": 2020,
         "sourceType": "module"
     }
 }
diff --git a/benchmark/data-min.js b/benchmark/data-min.js
new file mode 100644
index 0000000..6ecb61f
--- /dev/null
+++ b/benchmark/data-min.js
@@ -0,0 +1,12 @@
+/* eslint-disable */
+import{encode as k}from"sourcemap-codec";class p{constructor(t){this.bits=t instanceof p?t.bits.slice():[]}add(t){this.bits[t>>5]|=1<<(t&31)}has(t){return!!(this.bits[t>>5]&1<<(t&31))}}class g{constructor(t,e,n){this.start=t,this.end=e,this.original=n,this.intro="",this.outro="",this.content=n,this.storeName=!1,this.edited=!1,Object.defineProperties(this,{previous:{writable:!0,value:null},next:{writable:!0,value:null}})}appendLeft(t){this.outro+=t}appendRight(t){this.intro=this.intro+t}clone(){const t=new g(this.start,this.end,this.original);return t.intro=this.intro,t.outro=this.outro,t.content=this.content,t.storeName=this.storeName,t.edited=this.edited,t}contains(t){return this.start<t&&t<this.end}eachNext(t){let e=this;for(;e;)t(e),e=e.next}eachPrevious(t){let e=this;for(;e;)t(e),e=e.previous}edit(t,e,n){return this.content=t,n||(this.intro="",this.outro=""),this.storeName=e,this.edited=!0,this}prependLeft(t){this.outro=t+this.outro}prependRight(t){this.intro=t+this.intro}split(t){const e=t-this.start,n=this.original.slice(0,e),i=this.original.slice(e);this.original=n;const r=new g(t,this.end,i);return r.outro=this.outro,this.outro="",this.end=t,this.edited?(r.edit("",!1),this.content=""):this.content=n,r.next=this.next,r.next&&(r.next.previous=r),r.previous=this,this.next=r,r}toString(){return this.intro+this.content+this.outro}trimEnd(t){if(this.outro=this.outro.replace(t,""),this.outro.length)return!0;const e=this.content.replace(t,"");if(e.length)return e!==this.content&&this.split(this.start+e.length).edit("",void 0,!0),!0;if(this.edit("",void 0,!0),this.intro=this.intro.replace(t,""),this.intro.length)return!0}trimStart(t){if(this.intro=this.intro.replace(t,""),this.intro.length)return!0;const e=this.content.replace(t,"");if(e.length)return e!==this.content&&(this.split(this.end-e.length),this.edit("",void 0,!0)),!0;if(this.edit("",void 0,!0),this.outro=this.outro.replace(t,""),this.outro.length)return!0}}let w=()=>{throw new Error("Unsupported environment: `window.btoa` or `Buffer` should be supported.")};typeof window<"u"&&typeof window.btoa=="function"?w=l=>window.btoa(unescape(encodeURIComponent(l))):typeof Buffer=="function"&&(w=l=>Buffer.from(l,"utf-8").toString("base64"));class b{constructor(t){this.version=3,this.file=t.file,this.sources=t.sources,this.sourcesContent=t.sourcesContent,this.names=t.names,this.mappings=k(t.mappings)}toString(){return JSON.stringify(this)}toUrl(){return"data:application/json;charset=utf-8;base64,"+w(this.toString())}}function L(l){const t=l.split(`
+`),e=t.filter(r=>/^\t+/.test(r)),n=t.filter(r=>/^ {2,}/.test(r));if(e.length===0&&n.length===0)return null;if(e.length>=n.length)return"	";const i=n.reduce((r,s)=>{const h=/^ +/.exec(s)[0].length;return Math.min(h,r)},1/0);return new Array(i+1).join(" ")}function E(l,t){const e=l.split(/[/\\]/),n=t.split(/[/\\]/);for(e.pop();e[0]===n[0];)e.shift(),n.shift();if(e.length){let i=e.length;for(;i--;)e[i]=".."}return e.concat(n).join("/")}const R=Object.prototype.toString;function x(l){return R.call(l)==="[object Object]"}function C(l){const t=l.split(`
+`),e=[];for(let n=0,i=0;n<t.length;n++)e.push(i),i+=t[n].length+1;return function(i){let r=0,s=e.length;for(;r<s;){const a=r+s>>1;i<e[a]?s=a:r=a+1}const h=r-1,o=i-e[h];return{line:h,column:o}}}class y{constructor(t){this.hires=t,this.generatedCodeLine=0,this.generatedCodeColumn=0,this.raw=[],this.rawSegments=this.raw[this.generatedCodeLine]=[],this.pending=null}addEdit(t,e,n,i){if(e.length){const r=[this.generatedCodeColumn,t,n.line,n.column];i>=0&&r.push(i),this.rawSegments.push(r)}else this.pending&&this.rawSegments.push(this.pending);this.advance(e),this.pending=null}addUneditedChunk(t,e,n,i,r){let s=e.start,h=!0;for(;s<e.end;)(this.hires||h||r.has(s))&&this.rawSegments.push([this.generatedCodeColumn,t,i.line,i.column]),n[s]===`
+`?(i.line+=1,i.column=0,this.generatedCodeLine+=1,this.raw[this.generatedCodeLine]=this.rawSegments=[],this.generatedCodeColumn=0,h=!0):(i.column+=1,this.generatedCodeColumn+=1,h=!1),s+=1;this.pending=null}advance(t){if(!t)return;const e=t.split(`
+`);if(e.length>1){for(let n=0;n<e.length-1;n++)this.generatedCodeLine++,this.raw[this.generatedCodeLine]=this.rawSegments=[];this.generatedCodeColumn=0}this.generatedCodeColumn+=e[e.length-1].length}}const d=`
+`,c={insertLeft:!1,insertRight:!1,storeName:!1};class f{constructor(t,e={}){const n=new g(0,t.length,t);Object.defineProperties(this,{original:{writable:!0,value:t},outro:{writable:!0,value:""},intro:{writable:!0,value:""},firstChunk:{writable:!0,value:n},lastChunk:{writable:!0,value:n},lastSearchedChunk:{writable:!0,value:n},byStart:{writable:!0,value:{}},byEnd:{writable:!0,value:{}},filename:{writable:!0,value:e.filename},indentExclusionRanges:{writable:!0,value:e.indentExclusionRanges},sourcemapLocations:{writable:!0,value:new p},storedNames:{writable:!0,value:{}},indentStr:{writable:!0,value:L(t)}}),this.byStart[0]=n,this.byEnd[t.length]=n}addSourcemapLocation(t){this.sourcemapLocations.add(t)}append(t){if(typeof t!="string")throw new TypeError("outro content must be a string");return this.outro+=t,this}appendLeft(t,e){if(typeof e!="string")throw new TypeError("inserted content must be a string");this._split(t);const n=this.byEnd[t];return n?n.appendLeft(e):this.intro+=e,this}appendRight(t,e){if(typeof e!="string")throw new TypeError("inserted content must be a string");this._split(t);const n=this.byStart[t];return n?n.appendRight(e):this.outro+=e,this}clone(){const t=new f(this.original,{filename:this.filename});let e=this.firstChunk,n=t.firstChunk=t.lastSearchedChunk=e.clone();for(;e;){t.byStart[n.start]=n,t.byEnd[n.end]=n;const i=e.next,r=i&&i.clone();r&&(n.next=r,r.previous=n,n=r),e=i}return t.lastChunk=n,this.indentExclusionRanges&&(t.indentExclusionRanges=this.indentExclusionRanges.slice()),t.sourcemapLocations=new p(this.sourcemapLocations),t.intro=this.intro,t.outro=this.outro,t}generateDecodedMap(t){t=t||{};const e=0,n=Object.keys(this.storedNames),i=new y(t.hires),r=C(this.original);return this.intro&&i.advance(this.intro),this.firstChunk.eachNext(s=>{const h=r(s.start);s.intro.length&&i.advance(s.intro),s.edited?i.addEdit(e,s.content,h,s.storeName?n.indexOf(s.original):-1):i.addUneditedChunk(e,s,this.original,h,this.sourcemapLocations),s.outro.length&&i.advance(s.outro)}),{file:t.file?t.file.split(/[/\\]/).pop():null,sources:[t.source?E(t.file||"",t.source):null],sourcesContent:t.includeContent?[this.original]:[null],names:n,mappings:i.raw}}generateMap(t){return new b(this.generateDecodedMap(t))}getIndentString(){return this.indentStr===null?"	":this.indentStr}indent(t,e){const n=/^[^\r\n]/gm;if(x(t)&&(e=t,t=void 0),t=t!==void 0?t:this.indentStr||"	",t==="")return this;e=e||{};const i={};e.exclude&&(typeof e.exclude[0]=="number"?[e.exclude]:e.exclude).forEach(u=>{for(let m=u[0];m<u[1];m+=1)i[m]=!0});let r=e.indentStart!==!1;const s=a=>r?`${t}${a}`:(r=!0,a);this.intro=this.intro.replace(n,s);let h=0,o=this.firstChunk;for(;o;){const a=o.end;if(o.edited)i[h]||(o.content=o.content.replace(n,s),o.content.length&&(r=o.content[o.content.length-1]===`
+`));else for(h=o.start;h<a;){if(!i[h]){const u=this.original[h];u===`
+`?r=!0:u!=="\r"&&r&&(r=!1,h===o.start||(this._splitChunk(o,h),o=o.next),o.prependRight(t))}h+=1}h=o.end,o=o.next}return this.outro=this.outro.replace(n,s),this}insert(){throw new Error("magicString.insert(...) is deprecated. Use prependRight(...) or appendLeft(...)")}insertLeft(t,e){return c.insertLeft||(console.warn("magicString.insertLeft(...) is deprecated. Use magicString.appendLeft(...) instead"),c.insertLeft=!0),this.appendLeft(t,e)}insertRight(t,e){return c.insertRight||(console.warn("magicString.insertRight(...) is deprecated. Use magicString.prependRight(...) instead"),c.insertRight=!0),this.prependRight(t,e)}move(t,e,n){if(n>=t&&n<=e)throw new Error("Cannot move a selection inside itself");this._split(t),this._split(e),this._split(n);const i=this.byStart[t],r=this.byEnd[e],s=i.previous,h=r.next,o=this.byStart[n];if(!o&&r===this.lastChunk)return this;const a=o?o.previous:this.lastChunk;return s&&(s.next=h),h&&(h.previous=s),a&&(a.next=i),o&&(o.previous=r),i.previous||(this.firstChunk=r.next),r.next||(this.lastChunk=i.previous,this.lastChunk.next=null),i.previous=a,r.next=o||null,a||(this.firstChunk=i),o||(this.lastChunk=r),this}overwrite(t,e,n,i){if(typeof n!="string")throw new TypeError("replacement content must be a string");for(;t<0;)t+=this.original.length;for(;e<0;)e+=this.original.length;if(e>this.original.length)throw new Error("end is out of bounds");if(t===e)throw new Error("Cannot overwrite a zero-length range \u2013 use appendLeft or prependRight instead");this._split(t),this._split(e),i===!0&&(c.storeName||(console.warn("The final argument to magicString.overwrite(...) should be an options object. See https://github.com/rich-harris/magic-string"),c.storeName=!0),i={storeName:!0});const r=i!==void 0?i.storeName:!1,s=i!==void 0?i.contentOnly:!1;if(r){const a=this.original.slice(t,e);Object.defineProperty(this.storedNames,a,{writable:!0,value:!0,enumerable:!0})}const h=this.byStart[t],o=this.byEnd[e];if(h){let a=h;for(;a!==o;){if(a.next!==this.byStart[a.end])throw new Error("Cannot overwrite across a split point");a=a.next,a.edit("",!1)}h.edit(n,r,s)}else{const a=new g(t,e,"").edit(n,r);o.next=a,a.previous=o}return this}prepend(t){if(typeof t!="string")throw new TypeError("outro content must be a string");return this.intro=t+this.intro,this}prependLeft(t,e){if(typeof e!="string")throw new TypeError("inserted content must be a string");this._split(t);const n=this.byEnd[t];return n?n.prependLeft(e):this.intro=e+this.intro,this}prependRight(t,e){if(typeof e!="string")throw new TypeError("inserted content must be a string");this._split(t);const n=this.byStart[t];return n?n.prependRight(e):this.outro=e+this.outro,this}remove(t,e){for(;t<0;)t+=this.original.length;for(;e<0;)e+=this.original.length;if(t===e)return this;if(t<0||e>this.original.length)throw new Error("Character is out of bounds");if(t>e)throw new Error("end must be greater than start");this._split(t),this._split(e);let n=this.byStart[t];for(;n;)n.intro="",n.outro="",n.edit(""),n=e>n.end?this.byStart[n.end]:null;return this}lastChar(){if(this.outro.length)return this.outro[this.outro.length-1];let t=this.lastChunk;do{if(t.outro.length)return t.outro[t.outro.length-1];if(t.content.length)return t.content[t.content.length-1];if(t.intro.length)return t.intro[t.intro.length-1]}while(t=t.previous);return this.intro.length?this.intro[this.intro.length-1]:""}lastLine(){let t=this.outro.lastIndexOf(d);if(t!==-1)return this.outro.substr(t+1);let e=this.outro,n=this.lastChunk;do{if(n.outro.length>0){if(t=n.outro.lastIndexOf(d),t!==-1)return n.outro.substr(t+1)+e;e=n.outro+e}if(n.content.length>0){if(t=n.content.lastIndexOf(d),t!==-1)return n.content.substr(t+1)+e;e=n.content+e}if(n.intro.length>0){if(t=n.intro.lastIndexOf(d),t!==-1)return n.intro.substr(t+1)+e;e=n.intro+e}}while(n=n.previous);return t=this.intro.lastIndexOf(d),t!==-1?this.intro.substr(t+1)+e:this.intro+e}slice(t=0,e=this.original.length){for(;t<0;)t+=this.original.length;for(;e<0;)e+=this.original.length;let n="",i=this.firstChunk;for(;i&&(i.start>t||i.end<=t);){if(i.start<e&&i.end>=e)return n;i=i.next}if(i&&i.edited&&i.start!==t)throw new Error(`Cannot use replaced character ${t} as slice start anchor.`);const r=i;for(;i;){i.intro&&(r!==i||i.start===t)&&(n+=i.intro);const s=i.start<e&&i.end>=e;if(s&&i.edited&&i.end!==e)throw new Error(`Cannot use replaced character ${e} as slice end anchor.`);const h=r===i?t-i.start:0,o=s?i.content.length+e-i.end:i.content.length;if(n+=i.content.slice(h,o),i.outro&&(!s||i.end===e)&&(n+=i.outro),s)break;i=i.next}return n}snip(t,e){const n=this.clone();return n.remove(0,t),n.remove(e,n.original.length),n}_split(t){if(this.byStart[t]||this.byEnd[t])return;let e=this.lastSearchedChunk;const n=t>e.end;for(;e;){if(e.contains(t))return this._splitChunk(e,t);e=n?this.byStart[e.end]:this.byEnd[e.start]}}_splitChunk(t,e){if(t.edited&&t.content.length){const i=C(this.original)(e);throw new Error(`Cannot split a chunk that has already been edited (${i.line}:${i.column} \u2013 "${t.original}")`)}const n=t.split(e);return this.byEnd[e]=t,this.byStart[e]=n,this.byEnd[n.end]=n,t===this.lastChunk&&(this.lastChunk=n),this.lastSearchedChunk=t,!0}toString(){let t=this.intro,e=this.firstChunk;for(;e;)t+=e.toString(),e=e.next;return t+this.outro}isEmpty(){let t=this.firstChunk;do if(t.intro.length&&t.intro.trim()||t.content.length&&t.content.trim()||t.outro.length&&t.outro.trim())return!1;while(t=t.next);return!0}length(){let t=this.firstChunk,e=0;do e+=t.intro.length+t.content.length+t.outro.length;while(t=t.next);return e}trimLines(){return this.trim("[\\r\\n]")}trim(t){return this.trimStart(t).trimEnd(t)}trimEndAborted(t){const e=new RegExp((t||"\\s")+"+$");if(this.outro=this.outro.replace(e,""),this.outro.length)return!0;let n=this.lastChunk;do{const i=n.end,r=n.trimEnd(e);if(n.end!==i&&(this.lastChunk===n&&(this.lastChunk=n.next),this.byEnd[n.end]=n,this.byStart[n.next.start]=n.next,this.byEnd[n.next.end]=n.next),r)return!0;n=n.previous}while(n);return!1}trimEnd(t){return this.trimEndAborted(t),this}trimStartAborted(t){const e=new RegExp("^"+(t||"\\s")+"+");if(this.intro=this.intro.replace(e,""),this.intro.length)return!0;let n=this.firstChunk;do{const i=n.end,r=n.trimStart(e);if(n.end!==i&&(n===this.lastChunk&&(this.lastChunk=n.next),this.byEnd[n.end]=n,this.byStart[n.next.start]=n.next,this.byEnd[n.next.end]=n.next),r)return!0;n=n.next}while(n);return!1}trimStart(t){return this.trimStartAborted(t),this}hasChanged(){return this.original!==this.toString()}replace(t,e){function n(r,s){return typeof e=="string"?e.replace(/\$(\$|&|\d+)/g,(h,o)=>o==="$"?"$":o==="&"?r[0]:+o<r.length?r[+o]:`$${o}`):e(...r,r.index,s,r.groups)}function i(r,s){let h;const o=[];for(;h=r.exec(s);)o.push(h);return o}if(typeof t!="string"&&t.global)i(t,this.original).forEach(s=>{s.index!=null&&this.overwrite(s.index,s.index+s[0].length,n(s,this.original))});else{const r=this.original.match(t);r&&r.index!=null&&this.overwrite(r.index,r.index+r[0].length,n(r,this.original))}return this}}const v=Object.prototype.hasOwnProperty;class S{constructor(t={}){this.intro=t.intro||"",this.separator=t.separator!==void 0?t.separator:`
+`,this.sources=[],this.uniqueSources=[],this.uniqueSourceIndexByFilename={}}addSource(t){if(t instanceof f)return this.addSource({content:t,filename:t.filename,separator:this.separator});if(!x(t)||!t.content)throw new Error("bundle.addSource() takes an object with a `content` property, which should be an instance of MagicString, and an optional `filename`");if(["filename","indentExclusionRanges","separator"].forEach(e=>{v.call(t,e)||(t[e]=t.content[e])}),t.separator===void 0&&(t.separator=this.separator),t.filename)if(!v.call(this.uniqueSourceIndexByFilename,t.filename))this.uniqueSourceIndexByFilename[t.filename]=this.uniqueSources.length,this.uniqueSources.push({filename:t.filename,content:t.content.original});else{const e=this.uniqueSources[this.uniqueSourceIndexByFilename[t.filename]];if(t.content.original!==e.content)throw new Error(`Illegal source: same filename (${t.filename}), different contents`)}return this.sources.push(t),this}append(t,e){return this.addSource({content:new f(t),separator:e&&e.separator||""}),this}clone(){const t=new S({intro:this.intro,separator:this.separator});return this.sources.forEach(e=>{t.addSource({filename:e.filename,content:e.content.clone(),separator:e.separator})}),t}generateDecodedMap(t={}){const e=[];this.sources.forEach(i=>{Object.keys(i.content.storedNames).forEach(r=>{~e.indexOf(r)||e.push(r)})});const n=new y(t.hires);return this.intro&&n.advance(this.intro),this.sources.forEach((i,r)=>{r>0&&n.advance(this.separator);const s=i.filename?this.uniqueSourceIndexByFilename[i.filename]:-1,h=i.content,o=C(h.original);h.intro&&n.advance(h.intro),h.firstChunk.eachNext(a=>{const u=o(a.start);a.intro.length&&n.advance(a.intro),i.filename?a.edited?n.addEdit(s,a.content,u,a.storeName?e.indexOf(a.original):-1):n.addUneditedChunk(s,a,h.original,u,h.sourcemapLocations):n.advance(a.content),a.outro.length&&n.advance(a.outro)}),h.outro&&n.advance(h.outro)}),{file:t.file?t.file.split(/[/\\]/).pop():null,sources:this.uniqueSources.map(i=>t.file?E(t.file,i.filename):i.filename),sourcesContent:this.uniqueSources.map(i=>t.includeContent?i.content:null),names:e,mappings:n.raw}}generateMap(t){return new b(this.generateDecodedMap(t))}getIndentString(){const t={};return this.sources.forEach(e=>{const n=e.content.indentStr;n!==null&&(t[n]||(t[n]=0),t[n]+=1)}),Object.keys(t).sort((e,n)=>t[e]-t[n])[0]||"	"}indent(t){if(arguments.length||(t=this.getIndentString()),t==="")return this;let e=!this.intro||this.intro.slice(-1)===`
+`;return this.sources.forEach((n,i)=>{const r=n.separator!==void 0?n.separator:this.separator,s=e||i>0&&/\r?\n$/.test(r);n.content.indent(t,{exclude:n.indentExclusionRanges,indentStart:s}),e=n.content.lastChar()===`
+`}),this.intro&&(this.intro=t+this.intro.replace(/^[^\n]/gm,(n,i)=>i>0?t+n:n)),this}prepend(t){return this.intro=t+this.intro,this}toString(){const t=this.sources.map((e,n)=>{const i=e.separator!==void 0?e.separator:this.separator;return(n>0?i:"")+e.content.toString()}).join("");return this.intro+t}isEmpty(){return!(this.intro.length&&this.intro.trim()||this.sources.some(t=>!t.content.isEmpty()))}length(){return this.sources.reduce((t,e)=>t+e.content.length(),this.intro.length)}trimLines(){return this.trim("[\\r\\n]")}trim(t){return this.trimStart(t).trimEnd(t)}trimStart(t){const e=new RegExp("^"+(t||"\\s")+"+");if(this.intro=this.intro.replace(e,""),!this.intro){let n,i=0;do if(n=this.sources[i++],!n)break;while(!n.content.trimStartAborted(t))}return this}trimEnd(t){const e=new RegExp((t||"\\s")+"+$");let n,i=this.sources.length-1;do if(n=this.sources[i--],!n){this.intro=this.intro.replace(e,"");break}while(!n.content.trimEndAborted(t));return this}}export{S as Bundle,b as SourceMap,f as default};
diff --git a/benchmark/data.js b/benchmark/data.js
new file mode 100644
index 0000000..202d9c8
--- /dev/null
+++ b/benchmark/data.js
@@ -0,0 +1,1075 @@
+/* eslint-disable */
+import { encode } from "sourcemap-codec";
+class BitSet {
+  constructor(arg) {
+    this.bits = arg instanceof BitSet ? arg.bits.slice() : [];
+  }
+  add(n2) {
+    this.bits[n2 >> 5] |= 1 << (n2 & 31);
+  }
+  has(n2) {
+    return !!(this.bits[n2 >> 5] & 1 << (n2 & 31));
+  }
+}
+class Chunk {
+  constructor(start, end, content) {
+    this.start = start;
+    this.end = end;
+    this.original = content;
+    this.intro = "";
+    this.outro = "";
+    this.content = content;
+    this.storeName = false;
+    this.edited = false;
+    Object.defineProperties(this, {
+      previous: { writable: true, value: null },
+      next: { writable: true, value: null }
+    });
+  }
+  appendLeft(content) {
+    this.outro += content;
+  }
+  appendRight(content) {
+    this.intro = this.intro + content;
+  }
+  clone() {
+    const chunk = new Chunk(this.start, this.end, this.original);
+    chunk.intro = this.intro;
+    chunk.outro = this.outro;
+    chunk.content = this.content;
+    chunk.storeName = this.storeName;
+    chunk.edited = this.edited;
+    return chunk;
+  }
+  contains(index) {
+    return this.start < index && index < this.end;
+  }
+  eachNext(fn) {
+    let chunk = this;
+    while (chunk) {
+      fn(chunk);
+      chunk = chunk.next;
+    }
+  }
+  eachPrevious(fn) {
+    let chunk = this;
+    while (chunk) {
+      fn(chunk);
+      chunk = chunk.previous;
+    }
+  }
+  edit(content, storeName, contentOnly) {
+    this.content = content;
+    if (!contentOnly) {
+      this.intro = "";
+      this.outro = "";
+    }
+    this.storeName = storeName;
+    this.edited = true;
+    return this;
+  }
+  prependLeft(content) {
+    this.outro = content + this.outro;
+  }
+  prependRight(content) {
+    this.intro = content + this.intro;
+  }
+  split(index) {
+    const sliceIndex = index - this.start;
+    const originalBefore = this.original.slice(0, sliceIndex);
+    const originalAfter = this.original.slice(sliceIndex);
+    this.original = originalBefore;
+    const newChunk = new Chunk(index, this.end, originalAfter);
+    newChunk.outro = this.outro;
+    this.outro = "";
+    this.end = index;
+    if (this.edited) {
+      newChunk.edit("", false);
+      this.content = "";
+    } else {
+      this.content = originalBefore;
+    }
+    newChunk.next = this.next;
+    if (newChunk.next)
+      newChunk.next.previous = newChunk;
+    newChunk.previous = this;
+    this.next = newChunk;
+    return newChunk;
+  }
+  toString() {
+    return this.intro + this.content + this.outro;
+  }
+  trimEnd(rx) {
+    this.outro = this.outro.replace(rx, "");
+    if (this.outro.length)
+      return true;
+    const trimmed = this.content.replace(rx, "");
+    if (trimmed.length) {
+      if (trimmed !== this.content) {
+        this.split(this.start + trimmed.length).edit("", void 0, true);
+      }
+      return true;
+    } else {
+      this.edit("", void 0, true);
+      this.intro = this.intro.replace(rx, "");
+      if (this.intro.length)
+        return true;
+    }
+  }
+  trimStart(rx) {
+    this.intro = this.intro.replace(rx, "");
+    if (this.intro.length)
+      return true;
+    const trimmed = this.content.replace(rx, "");
+    if (trimmed.length) {
+      if (trimmed !== this.content) {
+        this.split(this.end - trimmed.length);
+        this.edit("", void 0, true);
+      }
+      return true;
+    } else {
+      this.edit("", void 0, true);
+      this.outro = this.outro.replace(rx, "");
+      if (this.outro.length)
+        return true;
+    }
+  }
+}
+let btoa = () => {
+  throw new Error("Unsupported environment: `window.btoa` or `Buffer` should be supported.");
+};
+if (typeof window !== "undefined" && typeof window.btoa === "function") {
+  btoa = (str) => window.btoa(unescape(encodeURIComponent(str)));
+} else if (typeof Buffer === "function") {
+  btoa = (str) => Buffer.from(str, "utf-8").toString("base64");
+}
+class SourceMap {
+  constructor(properties) {
+    this.version = 3;
+    this.file = properties.file;
+    this.sources = properties.sources;
+    this.sourcesContent = properties.sourcesContent;
+    this.names = properties.names;
+    this.mappings = encode(properties.mappings);
+  }
+  toString() {
+    return JSON.stringify(this);
+  }
+  toUrl() {
+    return "data:application/json;charset=utf-8;base64," + btoa(this.toString());
+  }
+}
+function guessIndent(code) {
+  const lines = code.split("\n");
+  const tabbed = lines.filter((line) => /^\t+/.test(line));
+  const spaced = lines.filter((line) => /^ {2,}/.test(line));
+  if (tabbed.length === 0 && spaced.length === 0) {
+    return null;
+  }
+  if (tabbed.length >= spaced.length) {
+    return "	";
+  }
+  const min = spaced.reduce((previous, current) => {
+    const numSpaces = /^ +/.exec(current)[0].length;
+    return Math.min(numSpaces, previous);
+  }, Infinity);
+  return new Array(min + 1).join(" ");
+}
+function getRelativePath(from, to) {
+  const fromParts = from.split(/[/\\]/);
+  const toParts = to.split(/[/\\]/);
+  fromParts.pop();
+  while (fromParts[0] === toParts[0]) {
+    fromParts.shift();
+    toParts.shift();
+  }
+  if (fromParts.length) {
+    let i = fromParts.length;
+    while (i--)
+      fromParts[i] = "..";
+  }
+  return fromParts.concat(toParts).join("/");
+}
+const toString = Object.prototype.toString;
+function isObject(thing) {
+  return toString.call(thing) === "[object Object]";
+}
+function getLocator(source) {
+  const originalLines = source.split("\n");
+  const lineOffsets = [];
+  for (let i = 0, pos = 0; i < originalLines.length; i++) {
+    lineOffsets.push(pos);
+    pos += originalLines[i].length + 1;
+  }
+  return function locate(index) {
+    let i = 0;
+    let j = lineOffsets.length;
+    while (i < j) {
+      const m = i + j >> 1;
+      if (index < lineOffsets[m]) {
+        j = m;
+      } else {
+        i = m + 1;
+      }
+    }
+    const line = i - 1;
+    const column = index - lineOffsets[line];
+    return { line, column };
+  };
+}
+class Mappings {
+  constructor(hires) {
+    this.hires = hires;
+    this.generatedCodeLine = 0;
+    this.generatedCodeColumn = 0;
+    this.raw = [];
+    this.rawSegments = this.raw[this.generatedCodeLine] = [];
+    this.pending = null;
+  }
+  addEdit(sourceIndex, content, loc, nameIndex) {
+    if (content.length) {
+      const segment = [this.generatedCodeColumn, sourceIndex, loc.line, loc.column];
+      if (nameIndex >= 0) {
+        segment.push(nameIndex);
+      }
+      this.rawSegments.push(segment);
+    } else if (this.pending) {
+      this.rawSegments.push(this.pending);
+    }
+    this.advance(content);
+    this.pending = null;
+  }
+  addUneditedChunk(sourceIndex, chunk, original, loc, sourcemapLocations) {
+    let originalCharIndex = chunk.start;
+    let first = true;
+    while (originalCharIndex < chunk.end) {
+      if (this.hires || first || sourcemapLocations.has(originalCharIndex)) {
+        this.rawSegments.push([this.generatedCodeColumn, sourceIndex, loc.line, loc.column]);
+      }
+      if (original[originalCharIndex] === "\n") {
+        loc.line += 1;
+        loc.column = 0;
+        this.generatedCodeLine += 1;
+        this.raw[this.generatedCodeLine] = this.rawSegments = [];
+        this.generatedCodeColumn = 0;
+        first = true;
+      } else {
+        loc.column += 1;
+        this.generatedCodeColumn += 1;
+        first = false;
+      }
+      originalCharIndex += 1;
+    }
+    this.pending = null;
+  }
+  advance(str) {
+    if (!str)
+      return;
+    const lines = str.split("\n");
+    if (lines.length > 1) {
+      for (let i = 0; i < lines.length - 1; i++) {
+        this.generatedCodeLine++;
+        this.raw[this.generatedCodeLine] = this.rawSegments = [];
+      }
+      this.generatedCodeColumn = 0;
+    }
+    this.generatedCodeColumn += lines[lines.length - 1].length;
+  }
+}
+const n = "\n";
+const warned = {
+  insertLeft: false,
+  insertRight: false,
+  storeName: false
+};
+class MagicString {
+  constructor(string, options = {}) {
+    const chunk = new Chunk(0, string.length, string);
+    Object.defineProperties(this, {
+      original: { writable: true, value: string },
+      outro: { writable: true, value: "" },
+      intro: { writable: true, value: "" },
+      firstChunk: { writable: true, value: chunk },
+      lastChunk: { writable: true, value: chunk },
+      lastSearchedChunk: { writable: true, value: chunk },
+      byStart: { writable: true, value: {} },
+      byEnd: { writable: true, value: {} },
+      filename: { writable: true, value: options.filename },
+      indentExclusionRanges: { writable: true, value: options.indentExclusionRanges },
+      sourcemapLocations: { writable: true, value: new BitSet() },
+      storedNames: { writable: true, value: {} },
+      indentStr: { writable: true, value: guessIndent(string) }
+    });
+    this.byStart[0] = chunk;
+    this.byEnd[string.length] = chunk;
+  }
+  addSourcemapLocation(char) {
+    this.sourcemapLocations.add(char);
+  }
+  append(content) {
+    if (typeof content !== "string")
+      throw new TypeError("outro content must be a string");
+    this.outro += content;
+    return this;
+  }
+  appendLeft(index, content) {
+    if (typeof content !== "string")
+      throw new TypeError("inserted content must be a string");
+    this._split(index);
+    const chunk = this.byEnd[index];
+    if (chunk) {
+      chunk.appendLeft(content);
+    } else {
+      this.intro += content;
+    }
+    return this;
+  }
+  appendRight(index, content) {
+    if (typeof content !== "string")
+      throw new TypeError("inserted content must be a string");
+    this._split(index);
+    const chunk = this.byStart[index];
+    if (chunk) {
+      chunk.appendRight(content);
+    } else {
+      this.outro += content;
+    }
+    return this;
+  }
+  clone() {
+    const cloned = new MagicString(this.original, { filename: this.filename });
+    let originalChunk = this.firstChunk;
+    let clonedChunk = cloned.firstChunk = cloned.lastSearchedChunk = originalChunk.clone();
+    while (originalChunk) {
+      cloned.byStart[clonedChunk.start] = clonedChunk;
+      cloned.byEnd[clonedChunk.end] = clonedChunk;
+      const nextOriginalChunk = originalChunk.next;
+      const nextClonedChunk = nextOriginalChunk && nextOriginalChunk.clone();
+      if (nextClonedChunk) {
+        clonedChunk.next = nextClonedChunk;
+        nextClonedChunk.previous = clonedChunk;
+        clonedChunk = nextClonedChunk;
+      }
+      originalChunk = nextOriginalChunk;
+    }
+    cloned.lastChunk = clonedChunk;
+    if (this.indentExclusionRanges) {
+      cloned.indentExclusionRanges = this.indentExclusionRanges.slice();
+    }
+    cloned.sourcemapLocations = new BitSet(this.sourcemapLocations);
+    cloned.intro = this.intro;
+    cloned.outro = this.outro;
+    return cloned;
+  }
+  generateDecodedMap(options) {
+    options = options || {};
+    const sourceIndex = 0;
+    const names = Object.keys(this.storedNames);
+    const mappings = new Mappings(options.hires);
+    const locate = getLocator(this.original);
+    if (this.intro) {
+      mappings.advance(this.intro);
+    }
+    this.firstChunk.eachNext((chunk) => {
+      const loc = locate(chunk.start);
+      if (chunk.intro.length)
+        mappings.advance(chunk.intro);
+      if (chunk.edited) {
+        mappings.addEdit(sourceIndex, chunk.content, loc, chunk.storeName ? names.indexOf(chunk.original) : -1);
+      } else {
+        mappings.addUneditedChunk(sourceIndex, chunk, this.original, loc, this.sourcemapLocations);
+      }
+      if (chunk.outro.length)
+        mappings.advance(chunk.outro);
+    });
+    return {
+      file: options.file ? options.file.split(/[/\\]/).pop() : null,
+      sources: [options.source ? getRelativePath(options.file || "", options.source) : null],
+      sourcesContent: options.includeContent ? [this.original] : [null],
+      names,
+      mappings: mappings.raw
+    };
+  }
+  generateMap(options) {
+    return new SourceMap(this.generateDecodedMap(options));
+  }
+  getIndentString() {
+    return this.indentStr === null ? "	" : this.indentStr;
+  }
+  indent(indentStr, options) {
+    const pattern = /^[^\r\n]/gm;
+    if (isObject(indentStr)) {
+      options = indentStr;
+      indentStr = void 0;
+    }
+    indentStr = indentStr !== void 0 ? indentStr : this.indentStr || "	";
+    if (indentStr === "")
+      return this;
+    options = options || {};
+    const isExcluded = {};
+    if (options.exclude) {
+      const exclusions = typeof options.exclude[0] === "number" ? [options.exclude] : options.exclude;
+      exclusions.forEach((exclusion) => {
+        for (let i = exclusion[0]; i < exclusion[1]; i += 1) {
+          isExcluded[i] = true;
+        }
+      });
+    }
+    let shouldIndentNextCharacter = options.indentStart !== false;
+    const replacer = (match) => {
+      if (shouldIndentNextCharacter)
+        return `${indentStr}${match}`;
+      shouldIndentNextCharacter = true;
+      return match;
+    };
+    this.intro = this.intro.replace(pattern, replacer);
+    let charIndex = 0;
+    let chunk = this.firstChunk;
+    while (chunk) {
+      const end = chunk.end;
+      if (chunk.edited) {
+        if (!isExcluded[charIndex]) {
+          chunk.content = chunk.content.replace(pattern, replacer);
+          if (chunk.content.length) {
+            shouldIndentNextCharacter = chunk.content[chunk.content.length - 1] === "\n";
+          }
+        }
+      } else {
+        charIndex = chunk.start;
+        while (charIndex < end) {
+          if (!isExcluded[charIndex]) {
+            const char = this.original[charIndex];
+            if (char === "\n") {
+              shouldIndentNextCharacter = true;
+            } else if (char !== "\r" && shouldIndentNextCharacter) {
+              shouldIndentNextCharacter = false;
+              if (charIndex === chunk.start) {
+                chunk.prependRight(indentStr);
+              } else {
+                this._splitChunk(chunk, charIndex);
+                chunk = chunk.next;
+                chunk.prependRight(indentStr);
+              }
+            }
+          }
+          charIndex += 1;
+        }
+      }
+      charIndex = chunk.end;
+      chunk = chunk.next;
+    }
+    this.outro = this.outro.replace(pattern, replacer);
+    return this;
+  }
+  insert() {
+    throw new Error("magicString.insert(...) is deprecated. Use prependRight(...) or appendLeft(...)");
+  }
+  insertLeft(index, content) {
+    if (!warned.insertLeft) {
+      console.warn("magicString.insertLeft(...) is deprecated. Use magicString.appendLeft(...) instead");
+      warned.insertLeft = true;
+    }
+    return this.appendLeft(index, content);
+  }
+  insertRight(index, content) {
+    if (!warned.insertRight) {
+      console.warn("magicString.insertRight(...) is deprecated. Use magicString.prependRight(...) instead");
+      warned.insertRight = true;
+    }
+    return this.prependRight(index, content);
+  }
+  move(start, end, index) {
+    if (index >= start && index <= end)
+      throw new Error("Cannot move a selection inside itself");
+    this._split(start);
+    this._split(end);
+    this._split(index);
+    const first = this.byStart[start];
+    const last = this.byEnd[end];
+    const oldLeft = first.previous;
+    const oldRight = last.next;
+    const newRight = this.byStart[index];
+    if (!newRight && last === this.lastChunk)
+      return this;
+    const newLeft = newRight ? newRight.previous : this.lastChunk;
+    if (oldLeft)
+      oldLeft.next = oldRight;
+    if (oldRight)
+      oldRight.previous = oldLeft;
+    if (newLeft)
+      newLeft.next = first;
+    if (newRight)
+      newRight.previous = last;
+    if (!first.previous)
+      this.firstChunk = last.next;
+    if (!last.next) {
+      this.lastChunk = first.previous;
+      this.lastChunk.next = null;
+    }
+    first.previous = newLeft;
+    last.next = newRight || null;
+    if (!newLeft)
+      this.firstChunk = first;
+    if (!newRight)
+      this.lastChunk = last;
+    return this;
+  }
+  overwrite(start, end, content, options) {
+    if (typeof content !== "string")
+      throw new TypeError("replacement content must be a string");
+    while (start < 0)
+      start += this.original.length;
+    while (end < 0)
+      end += this.original.length;
+    if (end > this.original.length)
+      throw new Error("end is out of bounds");
+    if (start === end)
+      throw new Error("Cannot overwrite a zero-length range \u2013 use appendLeft or prependRight instead");
+    this._split(start);
+    this._split(end);
+    if (options === true) {
+      if (!warned.storeName) {
+        console.warn("The final argument to magicString.overwrite(...) should be an options object. See https://github.com/rich-harris/magic-string");
+        warned.storeName = true;
+      }
+      options = { storeName: true };
+    }
+    const storeName = options !== void 0 ? options.storeName : false;
+    const contentOnly = options !== void 0 ? options.contentOnly : false;
+    if (storeName) {
+      const original = this.original.slice(start, end);
+      Object.defineProperty(this.storedNames, original, {
+        writable: true,
+        value: true,
+        enumerable: true
+      });
+    }
+    const first = this.byStart[start];
+    const last = this.byEnd[end];
+    if (first) {
+      let chunk = first;
+      while (chunk !== last) {
+        if (chunk.next !== this.byStart[chunk.end]) {
+          throw new Error("Cannot overwrite across a split point");
+        }
+        chunk = chunk.next;
+        chunk.edit("", false);
+      }
+      first.edit(content, storeName, contentOnly);
+    } else {
+      const newChunk = new Chunk(start, end, "").edit(content, storeName);
+      last.next = newChunk;
+      newChunk.previous = last;
+    }
+    return this;
+  }
+  prepend(content) {
+    if (typeof content !== "string")
+      throw new TypeError("outro content must be a string");
+    this.intro = content + this.intro;
+    return this;
+  }
+  prependLeft(index, content) {
+    if (typeof content !== "string")
+      throw new TypeError("inserted content must be a string");
+    this._split(index);
+    const chunk = this.byEnd[index];
+    if (chunk) {
+      chunk.prependLeft(content);
+    } else {
+      this.intro = content + this.intro;
+    }
+    return this;
+  }
+  prependRight(index, content) {
+    if (typeof content !== "string")
+      throw new TypeError("inserted content must be a string");
+    this._split(index);
+    const chunk = this.byStart[index];
+    if (chunk) {
+      chunk.prependRight(content);
+    } else {
+      this.outro = content + this.outro;
+    }
+    return this;
+  }
+  remove(start, end) {
+    while (start < 0)
+      start += this.original.length;
+    while (end < 0)
+      end += this.original.length;
+    if (start === end)
+      return this;
+    if (start < 0 || end > this.original.length)
+      throw new Error("Character is out of bounds");
+    if (start > end)
+      throw new Error("end must be greater than start");
+    this._split(start);
+    this._split(end);
+    let chunk = this.byStart[start];
+    while (chunk) {
+      chunk.intro = "";
+      chunk.outro = "";
+      chunk.edit("");
+      chunk = end > chunk.end ? this.byStart[chunk.end] : null;
+    }
+    return this;
+  }
+  lastChar() {
+    if (this.outro.length)
+      return this.outro[this.outro.length - 1];
+    let chunk = this.lastChunk;
+    do {
+      if (chunk.outro.length)
+        return chunk.outro[chunk.outro.length - 1];
+      if (chunk.content.length)
+        return chunk.content[chunk.content.length - 1];
+      if (chunk.intro.length)
+        return chunk.intro[chunk.intro.length - 1];
+    } while (chunk = chunk.previous);
+    if (this.intro.length)
+      return this.intro[this.intro.length - 1];
+    return "";
+  }
+  lastLine() {
+    let lineIndex = this.outro.lastIndexOf(n);
+    if (lineIndex !== -1)
+      return this.outro.substr(lineIndex + 1);
+    let lineStr = this.outro;
+    let chunk = this.lastChunk;
+    do {
+      if (chunk.outro.length > 0) {
+        lineIndex = chunk.outro.lastIndexOf(n);
+        if (lineIndex !== -1)
+          return chunk.outro.substr(lineIndex + 1) + lineStr;
+        lineStr = chunk.outro + lineStr;
+      }
+      if (chunk.content.length > 0) {
+        lineIndex = chunk.content.lastIndexOf(n);
+        if (lineIndex !== -1)
+          return chunk.content.substr(lineIndex + 1) + lineStr;
+        lineStr = chunk.content + lineStr;
+      }
+      if (chunk.intro.length > 0) {
+        lineIndex = chunk.intro.lastIndexOf(n);
+        if (lineIndex !== -1)
+          return chunk.intro.substr(lineIndex + 1) + lineStr;
+        lineStr = chunk.intro + lineStr;
+      }
+    } while (chunk = chunk.previous);
+    lineIndex = this.intro.lastIndexOf(n);
+    if (lineIndex !== -1)
+      return this.intro.substr(lineIndex + 1) + lineStr;
+    return this.intro + lineStr;
+  }
+  slice(start = 0, end = this.original.length) {
+    while (start < 0)
+      start += this.original.length;
+    while (end < 0)
+      end += this.original.length;
+    let result = "";
+    let chunk = this.firstChunk;
+    while (chunk && (chunk.start > start || chunk.end <= start)) {
+      if (chunk.start < end && chunk.end >= end) {
+        return result;
+      }
+      chunk = chunk.next;
+    }
+    if (chunk && chunk.edited && chunk.start !== start)
+      throw new Error(`Cannot use replaced character ${start} as slice start anchor.`);
+    const startChunk = chunk;
+    while (chunk) {
+      if (chunk.intro && (startChunk !== chunk || chunk.start === start)) {
+        result += chunk.intro;
+      }
+      const containsEnd = chunk.start < end && chunk.end >= end;
+      if (containsEnd && chunk.edited && chunk.end !== end)
+        throw new Error(`Cannot use replaced character ${end} as slice end anchor.`);
+      const sliceStart = startChunk === chunk ? start - chunk.start : 0;
+      const sliceEnd = containsEnd ? chunk.content.length + end - chunk.end : chunk.content.length;
+      result += chunk.content.slice(sliceStart, sliceEnd);
+      if (chunk.outro && (!containsEnd || chunk.end === end)) {
+        result += chunk.outro;
+      }
+      if (containsEnd) {
+        break;
+      }
+      chunk = chunk.next;
+    }
+    return result;
+  }
+  snip(start, end) {
+    const clone = this.clone();
+    clone.remove(0, start);
+    clone.remove(end, clone.original.length);
+    return clone;
+  }
+  _split(index) {
+    if (this.byStart[index] || this.byEnd[index])
+      return;
+    let chunk = this.lastSearchedChunk;
+    const searchForward = index > chunk.end;
+    while (chunk) {
+      if (chunk.contains(index))
+        return this._splitChunk(chunk, index);
+      chunk = searchForward ? this.byStart[chunk.end] : this.byEnd[chunk.start];
+    }
+  }
+  _splitChunk(chunk, index) {
+    if (chunk.edited && chunk.content.length) {
+      const loc = getLocator(this.original)(index);
+      throw new Error(`Cannot split a chunk that has already been edited (${loc.line}:${loc.column} \u2013 "${chunk.original}")`);
+    }
+    const newChunk = chunk.split(index);
+    this.byEnd[index] = chunk;
+    this.byStart[index] = newChunk;
+    this.byEnd[newChunk.end] = newChunk;
+    if (chunk === this.lastChunk)
+      this.lastChunk = newChunk;
+    this.lastSearchedChunk = chunk;
+    return true;
+  }
+  toString() {
+    let str = this.intro;
+    let chunk = this.firstChunk;
+    while (chunk) {
+      str += chunk.toString();
+      chunk = chunk.next;
+    }
+    return str + this.outro;
+  }
+  isEmpty() {
+    let chunk = this.firstChunk;
+    do {
+      if (chunk.intro.length && chunk.intro.trim() || chunk.content.length && chunk.content.trim() || chunk.outro.length && chunk.outro.trim())
+        return false;
+    } while (chunk = chunk.next);
+    return true;
+  }
+  length() {
+    let chunk = this.firstChunk;
+    let length = 0;
+    do {
+      length += chunk.intro.length + chunk.content.length + chunk.outro.length;
+    } while (chunk = chunk.next);
+    return length;
+  }
+  trimLines() {
+    return this.trim("[\\r\\n]");
+  }
+  trim(charType) {
+    return this.trimStart(charType).trimEnd(charType);
+  }
+  trimEndAborted(charType) {
+    const rx = new RegExp((charType || "\\s") + "+$");
+    this.outro = this.outro.replace(rx, "");
+    if (this.outro.length)
+      return true;
+    let chunk = this.lastChunk;
+    do {
+      const end = chunk.end;
+      const aborted = chunk.trimEnd(rx);
+      if (chunk.end !== end) {
+        if (this.lastChunk === chunk) {
+          this.lastChunk = chunk.next;
+        }
+        this.byEnd[chunk.end] = chunk;
+        this.byStart[chunk.next.start] = chunk.next;
+        this.byEnd[chunk.next.end] = chunk.next;
+      }
+      if (aborted)
+        return true;
+      chunk = chunk.previous;
+    } while (chunk);
+    return false;
+  }
+  trimEnd(charType) {
+    this.trimEndAborted(charType);
+    return this;
+  }
+  trimStartAborted(charType) {
+    const rx = new RegExp("^" + (charType || "\\s") + "+");
+    this.intro = this.intro.replace(rx, "");
+    if (this.intro.length)
+      return true;
+    let chunk = this.firstChunk;
+    do {
+      const end = chunk.end;
+      const aborted = chunk.trimStart(rx);
+      if (chunk.end !== end) {
+        if (chunk === this.lastChunk)
+          this.lastChunk = chunk.next;
+        this.byEnd[chunk.end] = chunk;
+        this.byStart[chunk.next.start] = chunk.next;
+        this.byEnd[chunk.next.end] = chunk.next;
+      }
+      if (aborted)
+        return true;
+      chunk = chunk.next;
+    } while (chunk);
+    return false;
+  }
+  trimStart(charType) {
+    this.trimStartAborted(charType);
+    return this;
+  }
+  hasChanged() {
+    return this.original !== this.toString();
+  }
+  replace(searchValue, replacement) {
+    function getReplacement(match, str) {
+      if (typeof replacement === "string") {
+        return replacement.replace(/\$(\$|&|\d+)/g, (_, i) => {
+          if (i === "$")
+            return "$";
+          if (i === "&")
+            return match[0];
+          const num = +i;
+          if (num < match.length)
+            return match[+i];
+          return `$${i}`;
+        });
+      } else {
+        return replacement(...match, match.index, str, match.groups);
+      }
+    }
+    function matchAll(re, str) {
+      let match;
+      const matches = [];
+      while (match = re.exec(str)) {
+        matches.push(match);
+      }
+      return matches;
+    }
+    if (typeof searchValue !== "string" && searchValue.global) {
+      const matches = matchAll(searchValue, this.original);
+      matches.forEach((match) => {
+        if (match.index != null)
+          this.overwrite(match.index, match.index + match[0].length, getReplacement(match, this.original));
+      });
+    } else {
+      const match = this.original.match(searchValue);
+      if (match && match.index != null)
+        this.overwrite(match.index, match.index + match[0].length, getReplacement(match, this.original));
+    }
+    return this;
+  }
+}
+const hasOwnProp = Object.prototype.hasOwnProperty;
+class Bundle {
+  constructor(options = {}) {
+    this.intro = options.intro || "";
+    this.separator = options.separator !== void 0 ? options.separator : "\n";
+    this.sources = [];
+    this.uniqueSources = [];
+    this.uniqueSourceIndexByFilename = {};
+  }
+  addSource(source) {
+    if (source instanceof MagicString) {
+      return this.addSource({
+        content: source,
+        filename: source.filename,
+        separator: this.separator
+      });
+    }
+    if (!isObject(source) || !source.content) {
+      throw new Error("bundle.addSource() takes an object with a `content` property, which should be an instance of MagicString, and an optional `filename`");
+    }
+    ["filename", "indentExclusionRanges", "separator"].forEach((option) => {
+      if (!hasOwnProp.call(source, option))
+        source[option] = source.content[option];
+    });
+    if (source.separator === void 0) {
+      source.separator = this.separator;
+    }
+    if (source.filename) {
+      if (!hasOwnProp.call(this.uniqueSourceIndexByFilename, source.filename)) {
+        this.uniqueSourceIndexByFilename[source.filename] = this.uniqueSources.length;
+        this.uniqueSources.push({ filename: source.filename, content: source.content.original });
+      } else {
+        const uniqueSource = this.uniqueSources[this.uniqueSourceIndexByFilename[source.filename]];
+        if (source.content.original !== uniqueSource.content) {
+          throw new Error(`Illegal source: same filename (${source.filename}), different contents`);
+        }
+      }
+    }
+    this.sources.push(source);
+    return this;
+  }
+  append(str, options) {
+    this.addSource({
+      content: new MagicString(str),
+      separator: options && options.separator || ""
+    });
+    return this;
+  }
+  clone() {
+    const bundle = new Bundle({
+      intro: this.intro,
+      separator: this.separator
+    });
+    this.sources.forEach((source) => {
+      bundle.addSource({
+        filename: source.filename,
+        content: source.content.clone(),
+        separator: source.separator
+      });
+    });
+    return bundle;
+  }
+  generateDecodedMap(options = {}) {
+    const names = [];
+    this.sources.forEach((source) => {
+      Object.keys(source.content.storedNames).forEach((name) => {
+        if (!~names.indexOf(name))
+          names.push(name);
+      });
+    });
+    const mappings = new Mappings(options.hires);
+    if (this.intro) {
+      mappings.advance(this.intro);
+    }
+    this.sources.forEach((source, i) => {
+      if (i > 0) {
+        mappings.advance(this.separator);
+      }
+      const sourceIndex = source.filename ? this.uniqueSourceIndexByFilename[source.filename] : -1;
+      const magicString = source.content;
+      const locate = getLocator(magicString.original);
+      if (magicString.intro) {
+        mappings.advance(magicString.intro);
+      }
+      magicString.firstChunk.eachNext((chunk) => {
+        const loc = locate(chunk.start);
+        if (chunk.intro.length)
+          mappings.advance(chunk.intro);
+        if (source.filename) {
+          if (chunk.edited) {
+            mappings.addEdit(sourceIndex, chunk.content, loc, chunk.storeName ? names.indexOf(chunk.original) : -1);
+          } else {
+            mappings.addUneditedChunk(sourceIndex, chunk, magicString.original, loc, magicString.sourcemapLocations);
+          }
+        } else {
+          mappings.advance(chunk.content);
+        }
+        if (chunk.outro.length)
+          mappings.advance(chunk.outro);
+      });
+      if (magicString.outro) {
+        mappings.advance(magicString.outro);
+      }
+    });
+    return {
+      file: options.file ? options.file.split(/[/\\]/).pop() : null,
+      sources: this.uniqueSources.map((source) => {
+        return options.file ? getRelativePath(options.file, source.filename) : source.filename;
+      }),
+      sourcesContent: this.uniqueSources.map((source) => {
+        return options.includeContent ? source.content : null;
+      }),
+      names,
+      mappings: mappings.raw
+    };
+  }
+  generateMap(options) {
+    return new SourceMap(this.generateDecodedMap(options));
+  }
+  getIndentString() {
+    const indentStringCounts = {};
+    this.sources.forEach((source) => {
+      const indentStr = source.content.indentStr;
+      if (indentStr === null)
+        return;
+      if (!indentStringCounts[indentStr])
+        indentStringCounts[indentStr] = 0;
+      indentStringCounts[indentStr] += 1;
+    });
+    return Object.keys(indentStringCounts).sort((a, b) => {
+      return indentStringCounts[a] - indentStringCounts[b];
+    })[0] || "	";
+  }
+  indent(indentStr) {
+    if (!arguments.length) {
+      indentStr = this.getIndentString();
+    }
+    if (indentStr === "")
+      return this;
+    let trailingNewline = !this.intro || this.intro.slice(-1) === "\n";
+    this.sources.forEach((source, i) => {
+      const separator = source.separator !== void 0 ? source.separator : this.separator;
+      const indentStart = trailingNewline || i > 0 && /\r?\n$/.test(separator);
+      source.content.indent(indentStr, {
+        exclude: source.indentExclusionRanges,
+        indentStart
+      });
+      trailingNewline = source.content.lastChar() === "\n";
+    });
+    if (this.intro) {
+      this.intro = indentStr + this.intro.replace(/^[^\n]/gm, (match, index) => {
+        return index > 0 ? indentStr + match : match;
+      });
+    }
+    return this;
+  }
+  prepend(str) {
+    this.intro = str + this.intro;
+    return this;
+  }
+  toString() {
+    const body = this.sources.map((source, i) => {
+      const separator = source.separator !== void 0 ? source.separator : this.separator;
+      const str = (i > 0 ? separator : "") + source.content.toString();
+      return str;
+    }).join("");
+    return this.intro + body;
+  }
+  isEmpty() {
+    if (this.intro.length && this.intro.trim())
+      return false;
+    if (this.sources.some((source) => !source.content.isEmpty()))
+      return false;
+    return true;
+  }
+  length() {
+    return this.sources.reduce((length, source) => length + source.content.length(), this.intro.length);
+  }
+  trimLines() {
+    return this.trim("[\\r\\n]");
+  }
+  trim(charType) {
+    return this.trimStart(charType).trimEnd(charType);
+  }
+  trimStart(charType) {
+    const rx = new RegExp("^" + (charType || "\\s") + "+");
+    this.intro = this.intro.replace(rx, "");
+    if (!this.intro) {
+      let source;
+      let i = 0;
+      do {
+        source = this.sources[i++];
+        if (!source) {
+          break;
+        }
+      } while (!source.content.trimStartAborted(charType));
+    }
+    return this;
+  }
+  trimEnd(charType) {
+    const rx = new RegExp((charType || "\\s") + "+$");
+    let source;
+    let i = this.sources.length - 1;
+    do {
+      source = this.sources[i--];
+      if (!source) {
+        this.intro = this.intro.replace(rx, "");
+        break;
+      }
+    } while (!source.content.trimEndAborted(charType));
+    return this;
+  }
+}
+export {
+  Bundle,
+  SourceMap,
+  MagicString as default
+};
diff --git a/benchmark/index.mjs b/benchmark/index.mjs
new file mode 100644
index 0000000..1898a7a
--- /dev/null
+++ b/benchmark/index.mjs
@@ -0,0 +1,80 @@
+import Benchmark from 'benchmark';
+import MagicString from '../dist/magic-string.es.mjs';
+import fs from 'fs/promises';
+
+Benchmark.support.decompilation = false;
+
+console.log(`node ${process.version}\n`);
+
+function runWithInstance(name, inputs, func, setup) {
+	const ss = [];
+	return new Benchmark(
+		name,
+		{
+			setup: () => {
+				for (const [i, input] of inputs.entries()) {
+					ss[i] = new MagicString(input);
+					if (setup) {
+						setup(ss[i]);
+					}
+				}
+			},
+			fn: () => {
+				for (const i of inputs.keys()) {
+					func(ss[i]);
+				}
+			}
+		}
+	).on('complete', (event) => {
+		console.log(String(event.target));
+	}).on('error', (event) => {
+		console.error(event.target.error);
+	}).run();
+}
+
+async function bench() {
+	const inputs = await Promise.all(
+		['data.js', 'data-min.js'].map(
+			(file) => fs.readFile(new URL(file, import.meta.url), 'utf-8')
+		)
+	);
+
+		new Benchmark('construct', {
+			fn: () => {
+				for (const input of inputs) {
+					new MagicString(input);
+				}
+			}
+		}).on('complete', (event) => {
+			console.log(String(event.target));
+		}).on('error', (event) => {
+			console.error(event.target.error);
+		}).run()
+
+	runWithInstance('append', inputs, s => {
+		s.append(';"append";');
+	});
+	runWithInstance('indent', inputs, s => {
+		s.indent();
+	});
+
+	runWithInstance('generateMap (no edit)', inputs, s => {
+		s.generateMap();
+	});
+	runWithInstance('generateMap (edit)', inputs, s => {
+		s.generateMap();
+	}, s => {
+		s.replace(/replacement/g, 'replacement\nReplacement');
+	});
+
+	runWithInstance('generateDecodedMap (no edit)', inputs, s => {
+		s.generateDecodedMap();
+	});
+	runWithInstance('generateDecodedMap (edit)', inputs, s => {
+		s.generateDecodedMap();
+	}, s => {
+		s.replace(/replacement/g, 'replacement\nReplacement');
+	});
+}
+
+bench();
diff --git a/package-lock.json b/package-lock.json
index 8106bea..c49cd48 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -6,7 +6,7 @@
   "packages": {
     "": {
       "name": "magic-string",
-      "version": "0.26.1",
+      "version": "0.26.2",
       "license": "MIT",
       "dependencies": {
         "sourcemap-codec": "^1.4.8"
@@ -14,6 +14,7 @@
       "devDependencies": {
         "@rollup/plugin-node-resolve": "^13.1.3",
         "@rollup/plugin-replace": "^4.0.0",
+        "benchmark": "^2.1.4",
         "bumpp": "^7.1.1",
         "conventional-changelog-cli": "^2.2.2",
         "eslint": "^8.10.0",
@@ -397,6 +398,16 @@
       "integrity": "sha1-ibTRmasr7kneFk6gK4nORi1xt2c=",
       "dev": true
     },
+    "node_modules/benchmark": {
+      "version": "2.1.4",
+      "resolved": "https://registry.npmjs.org/benchmark/-/benchmark-2.1.4.tgz",
+      "integrity": "sha512-l9MlfN4M1K/H2fbhfMy3B7vJd6AGKJVQn2h6Sg/Yx+KckoUA7ewS5Vv6TjSq18ooE1kS9hhAlQRH3AkXIh/aOQ==",
+      "dev": true,
+      "dependencies": {
+        "lodash": "^4.17.4",
+        "platform": "^1.3.3"
+      }
+    },
     "node_modules/binary-extensions": {
       "version": "2.2.0",
       "resolved": "https://registry.npmjs.org/binary-extensions/-/binary-extensions-2.2.0.tgz",
@@ -2914,6 +2925,12 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/platform": {
+      "version": "1.3.6",
+      "resolved": "https://registry.npmjs.org/platform/-/platform-1.3.6.tgz",
+      "integrity": "sha512-fnWVljUchTro6RiCFvCXBbNhJc2NijN7oIQxbwsyL0buWJPG85v81ehlHI9fXrJsMNgTofEoWIQeClKpgxFLrg==",
+      "dev": true
+    },
     "node_modules/prelude-ls": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/prelude-ls/-/prelude-ls-1.2.1.tgz",
@@ -4169,6 +4186,16 @@
       "integrity": "sha1-ibTRmasr7kneFk6gK4nORi1xt2c=",
       "dev": true
     },
+    "benchmark": {
+      "version": "2.1.4",
+      "resolved": "https://registry.npmjs.org/benchmark/-/benchmark-2.1.4.tgz",
+      "integrity": "sha512-l9MlfN4M1K/H2fbhfMy3B7vJd6AGKJVQn2h6Sg/Yx+KckoUA7ewS5Vv6TjSq18ooE1kS9hhAlQRH3AkXIh/aOQ==",
+      "dev": true,
+      "requires": {
+        "lodash": "^4.17.4",
+        "platform": "^1.3.3"
+      }
+    },
     "binary-extensions": {
       "version": "2.2.0",
       "resolved": "https://registry.npmjs.org/binary-extensions/-/binary-extensions-2.2.0.tgz",
@@ -6069,6 +6096,12 @@
       "integrity": "sha1-7RQaasBDqEnqWISY59yosVMw6Qw=",
       "dev": true
     },
+    "platform": {
+      "version": "1.3.6",
+      "resolved": "https://registry.npmjs.org/platform/-/platform-1.3.6.tgz",
+      "integrity": "sha512-fnWVljUchTro6RiCFvCXBbNhJc2NijN7oIQxbwsyL0buWJPG85v81ehlHI9fXrJsMNgTofEoWIQeClKpgxFLrg==",
+      "dev": true
+    },
     "prelude-ls": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/prelude-ls/-/prelude-ls-1.2.1.tgz",
diff --git a/package.json b/package.json
index e231a97..703eed9 100644
--- a/package.json
+++ b/package.json
@@ -39,6 +39,7 @@
     "release": "bumpp -x \"npm run changelog\" --all --commit --tag --push && npm publish",
     "pretest": "npm run lint && npm run build",
     "test": "mocha",
+    "bench": "npm run build && node benchmark/index.mjs",
     "watch": "rollup -cw"
   },
   "dependencies": {
@@ -47,6 +48,7 @@
   "devDependencies": {
     "@rollup/plugin-node-resolve": "^13.1.3",
     "@rollup/plugin-replace": "^4.0.0",
+    "benchmark": "^2.1.4",
     "bumpp": "^7.1.1",
     "conventional-changelog-cli": "^2.2.2",
     "eslint": "^8.10.0",
diff --git a/src/Bundle.js b/src/Bundle.js
index 33b3768..e682fb5 100644
--- a/src/Bundle.js
+++ b/src/Bundle.js
@@ -164,7 +164,7 @@ export default class Bundle {
 		const indentStringCounts = {};
 
 		this.sources.forEach((source) => {
-			const indentStr = source.content.indentStr;
+			const indentStr = source.content._getRawIndentString();
 
 			if (indentStr === null) return;
 
diff --git a/src/MagicString.js b/src/MagicString.js
index d5e35bf..e45ad2e 100644
--- a/src/MagicString.js
+++ b/src/MagicString.js
@@ -33,7 +33,7 @@ export default class MagicString {
 			indentExclusionRanges: { writable: true, value: options.indentExclusionRanges },
 			sourcemapLocations: { writable: true, value: new BitSet() },
 			storedNames: { writable: true, value: {} },
-			indentStr: { writable: true, value: guessIndent(string) },
+			indentStr: { writable: true, value: undefined },
 		});
 
 		if (DEBUG) {
@@ -175,7 +175,19 @@ export default class MagicString {
 		return new SourceMap(this.generateDecodedMap(options));
 	}
 
+	_ensureindentStr() {
+		if (this.indentStr === undefined) {
+			this.indentStr = guessIndent(this.original);
+		}
+	}
+
+	_getRawIndentString() {
+		this._ensureindentStr();
+		return this.indentStr;
+	}
+
 	getIndentString() {
+		this._ensureindentStr();
 		return this.indentStr === null ? '\t' : this.indentStr;
 	}
 
@@ -187,7 +199,10 @@ export default class MagicString {
 			indentStr = undefined;
 		}
 
-		indentStr = indentStr !== undefined ? indentStr : this.indentStr || '\t';
+		if (indentStr === undefined) {
+			this._ensureindentStr();
+			indentStr = this.indentStr || '\t';
+		}
 
 		if (indentStr === '') return this; // noop