fix: add max depth limit and max edges limit (#56)

Co-authored-by: Matus Sabo <lamanabie@gmail.com>
davidmarkclements · Sep 7, 2021 · ce7db51 · ce7db51
1 parent 377166e
commit ce7db51
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Showing 6 changed files with 382 additions and 138 deletions.
diff --git a/.gitignore b/.gitignore
@@ -2,3 +2,4 @@
 node_modules/
 npm-debug.log
 yarn.lock
+package-lock.json
diff --git a/index.d.ts b/index.d.ts
@@ -1,8 +1,23 @@
-declare function stringify(value: any, replacer?: (key: string, value: any) => any, space?: string | number): string;
+declare function stringify(
+  value: any,
+  replacer?: (key: string, value: any) => any,
+  space?: string | number,
+  options?: { depthLimit: number | undefined; edgesLimit: number | undefined }
+): string;
 
 declare namespace stringify {
-  export function stable(value: any, replacer?: (key: string, value: any) => any, space?: string | number): string;
-  export function stableStringify(value: any, replacer?: (key: string, value: any) => any, space?: string | number): string;
+  export function stable(
+    value: any,
+    replacer?: (key: string, value: any) => any,
+    space?: string | number,
+    options?: { depthLimit: number | undefined; edgesLimit: number | undefined }
+  ): string;
+  export function stableStringify(
+    value: any,
+    replacer?: (key: string, value: any) => any,
+    space?: string | number,
+    options?: { depthLimit: number | undefined; edgesLimit: number | undefined }
+  ): string;
 }
 
 export default stringify;
diff --git a/index.js b/index.js
@@ -3,12 +3,26 @@ stringify.default = stringify
 stringify.stable = deterministicStringify
 stringify.stableStringify = deterministicStringify
 
+var LIMIT_REPLACE_NODE = '[...]'
+var CIRCULAR_REPLACE_NODE = '[Circular]'
+
 var arr = []
 var replacerStack = []
 
+function defaultOptions () {
+  return {
+    depthLimit: 10,
+    edgesLimit: 20
+  }
+}
+
 // Regular stringify
-function stringify (obj, replacer, spacer) {
-  decirc(obj, '', [], undefined)
+function stringify (obj, replacer, spacer, options) {
+  if (typeof options === 'undefined') {
+    options = defaultOptions()
+  }
+
+  decirc(obj, '', 0, [], undefined, 0, options)
   var res
   try {
     if (replacerStack.length === 0) {
@@ -30,37 +44,60 @@ function stringify (obj, replacer, spacer) {
   }
   return res
 }
-function decirc (val, k, stack, parent) {
+
+function setReplace (replace, val, k, parent) {
+  var propertyDescriptor = Object.getOwnPropertyDescriptor(parent, k)
+  if (propertyDescriptor.get !== undefined) {
+    if (propertyDescriptor.configurable) {
+      Object.defineProperty(parent, k, { value: replace })
+      arr.push([parent, k, val, propertyDescriptor])
+    } else {
+      replacerStack.push([val, k, replace])
+    }
+  } else {
+    parent[k] = replace
+    arr.push([parent, k, val])
+  }
+}
+
+function decirc (val, k, edgeIndex, stack, parent, depth, options) {
+  depth += 1
   var i
   if (typeof val === 'object' && val !== null) {
     for (i = 0; i < stack.length; i++) {
       if (stack[i] === val) {
-        var propertyDescriptor = Object.getOwnPropertyDescriptor(parent, k)
-        if (propertyDescriptor.get !== undefined) {
-          if (propertyDescriptor.configurable) {
-            Object.defineProperty(parent, k, { value: '[Circular]' })
-            arr.push([parent, k, val, propertyDescriptor])
-          } else {
-            replacerStack.push([val, k])
-          }
-        } else {
-          parent[k] = '[Circular]'
-          arr.push([parent, k, val])
-        }
+        setReplace(CIRCULAR_REPLACE_NODE, val, k, parent)
         return
       }
     }
+
+    if (
+      typeof options.depthLimit !== 'undefined' &&
+      depth > options.depthLimit
+    ) {
+      setReplace(LIMIT_REPLACE_NODE, val, k, parent)
+      return
+    }
+
+    if (
+      typeof options.edgesLimit !== 'undefined' &&
+      edgeIndex + 1 > options.edgesLimit
+    ) {
+      setReplace(LIMIT_REPLACE_NODE, val, k, parent)
+      return
+    }
+
     stack.push(val)
     // Optimize for Arrays. Big arrays could kill the performance otherwise!
     if (Array.isArray(val)) {
       for (i = 0; i < val.length; i++) {
-        decirc(val[i], i, stack, val)
+        decirc(val[i], i, i, stack, val, depth, options)
       }
     } else {
       var keys = Object.keys(val)
       for (i = 0; i < keys.length; i++) {
         var key = keys[i]
-        decirc(val[key], key, stack, val)
+        decirc(val[key], key, i, stack, val, depth, options)
       }
     }
     stack.pop()
@@ -78,8 +115,12 @@ function compareFunction (a, b) {
   return 0
 }
 
-function deterministicStringify (obj, replacer, spacer) {
-  var tmp = deterministicDecirc(obj, '', [], undefined) || obj
+function deterministicStringify (obj, replacer, spacer, options) {
+  if (typeof options === 'undefined') {
+    options = defaultOptions()
+  }
+
+  var tmp = deterministicDecirc(obj, '', 0, [], undefined, 0, options) || obj
   var res
   try {
     if (replacerStack.length === 0) {
@@ -103,23 +144,13 @@ function deterministicStringify (obj, replacer, spacer) {
   return res
 }
 
-function deterministicDecirc (val, k, stack, parent) {
+function deterministicDecirc (val, k, edgeIndex, stack, parent, depth, options) {
+  depth += 1
   var i
   if (typeof val === 'object' && val !== null) {
     for (i = 0; i < stack.length; i++) {
       if (stack[i] === val) {
-        var propertyDescriptor = Object.getOwnPropertyDescriptor(parent, k)
-        if (propertyDescriptor.get !== undefined) {
-          if (propertyDescriptor.configurable) {
-            Object.defineProperty(parent, k, { value: '[Circular]' })
-            arr.push([parent, k, val, propertyDescriptor])
-          } else {
-            replacerStack.push([val, k])
-          }
-        } else {
-          parent[k] = '[Circular]'
-          arr.push([parent, k, val])
-        }
+        setReplace(CIRCULAR_REPLACE_NODE, val, k, parent)
         return
       }
     }
@@ -130,22 +161,39 @@ function deterministicDecirc (val, k, stack, parent) {
     } catch (_) {
       return
     }
+
+    if (
+      typeof options.depthLimit !== 'undefined' &&
+      depth > options.depthLimit
+    ) {
+      setReplace(LIMIT_REPLACE_NODE, val, k, parent)
+      return
+    }
+
+    if (
+      typeof options.edgesLimit !== 'undefined' &&
+      edgeIndex + 1 > options.edgesLimit
+    ) {
+      setReplace(LIMIT_REPLACE_NODE, val, k, parent)
+      return
+    }
+
     stack.push(val)
     // Optimize for Arrays. Big arrays could kill the performance otherwise!
     if (Array.isArray(val)) {
       for (i = 0; i < val.length; i++) {
-        deterministicDecirc(val[i], i, stack, val)
+        deterministicDecirc(val[i], i, i, stack, val, depth, options)
       }
     } else {
       // Create a temporary object in the required way
       var tmp = {}
       var keys = Object.keys(val).sort(compareFunction)
       for (i = 0; i < keys.length; i++) {
         var key = keys[i]
-        deterministicDecirc(val[key], key, stack, val)
+        deterministicDecirc(val[key], key, i, stack, val, depth, options)
         tmp[key] = val[key]
       }
-      if (parent !== undefined) {
+      if (typeof parent !== 'undefined') {
         arr.push([parent, k, val])
         parent[k] = tmp
       } else {
@@ -157,15 +205,20 @@ function deterministicDecirc (val, k, stack, parent) {
 }
 
 // wraps replacer function to handle values we couldn't replace
-// and mark them as [Circular]
+// and mark them as replaced value
 function replaceGetterValues (replacer) {
-  replacer = replacer !== undefined ? replacer : function (k, v) { return v }
+  replacer =
+    typeof replacer !== 'undefined'
+      ? replacer
+      : function (k, v) {
+        return v
+      }
   return function (key, val) {
     if (replacerStack.length > 0) {
       for (var i = 0; i < replacerStack.length; i++) {
         var part = replacerStack[i]
         if (part[1] === key && part[0] === val) {
-          val = '[Circular]'
+          val = part[2]
           replacerStack.splice(i, 1)
           break
         }

diff --git a/readme.md b/readme.md
@@ -13,7 +13,7 @@ handle circular structures. See the example below for further information.
 
 The same as [JSON.stringify][].
 
-`stringify(value[, replacer[, space]])`
+`stringify(value[, replacer[, space[, options]]])`
 
 ```js
 const safeStringify = require('fast-safe-stringify')
@@ -33,7 +33,14 @@ function replacer(key, value) {
   }
   return value
 }
-const serialized = safeStringify(o, replacer, 2)
+
+// those are also defaults limits when no options object is passed into safeStringify
+const options = {
+  depthLimit: 10,
+  edgesLimit: 20,
+};
+
+const serialized = safeStringify(o, replacer, 2, options)
 // Key: "" Value: {"a":1,"o":"[Circular]"}
 // Key: "a" Value: 1
 // Key: "o" Value: "[Circular]"
@@ -43,6 +50,7 @@ console.log(serialized)
 // }
 ```
 
+
 Using the deterministic version also works the same:
 
 ```js
@@ -62,6 +70,11 @@ A faster and side-effect free implementation is available in the
 [safe-stable-stringify][] module. However it is still considered experimental
 due to a new and more complex implementation.
 
+### Replace strings constants
+
+- `[Circular]` - when same reference is found
+- `[...]` - when some limit from options object is reached
+
 ## Differences to JSON.stringify
 
 In general the behavior is identical to [JSON.stringify][]. The [`replacer`][]
@@ -153,4 +166,4 @@ MIT
 [`space`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#The%20space%20argument
 [`toJSON`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#toJSON()_behavior
 [benchmark]: https://github.com/epoberezkin/fast-json-stable-stringify/blob/67f688f7441010cfef91a6147280cc501701e83b/benchmark
-[JSON.stringify]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify
+[JSON.stringify]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify