Merge pull request #62 from leebyron/fix-slice

FIX: slice considers intro/outro, no throw after removal
Rich-Harris · May 14, 2016 · 2266efb · 2266efb
2 parents e2cd263 + 7d280ef
commit 2266efb
Show file tree

Hide file tree

Showing 2 changed files with 106 additions and 11 deletions.
diff --git a/src/MagicString.js b/src/MagicString.js
@@ -352,23 +352,46 @@ MagicString.prototype = {
 		return this.overwrite( start, end, '', false );
 	},
 
-	slice ( start, end = this.original.length ) {
+	slice ( start = 0, end = this.original.length ) {
 		while ( start < 0 ) start += this.original.length;
 		while ( end < 0 ) end += this.original.length;
 
 		let result = '';
 
+		// find start chunk
 		let chunk = this.firstChunk;
+		while ( chunk && ( chunk.start > start || chunk.end <= start ) ) {
+
+			// found end chunk before 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 ${start} as slice start anchor.`);
+
+		let startChunk = chunk;
 		while ( chunk ) {
-			if ( chunk.start < start || chunk.end > end ) {
-				if ( chunk.edited ) throw new Error( `Cannot use replaced characters (${start}, ${end}) as slice anchors` );
+			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 = Math.max( start - chunk.start, 0 );
-				const sliceEnd = Math.min( chunk.content.length - ( chunk.end - end ), chunk.content.length );
+			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;
+			}
 
-				result += chunk.content.slice( sliceStart, sliceEnd );
-			} else if ( chunk.end > start && chunk.start < end ) {
-				result += chunk.content;
+			if ( containsEnd ) {
+				break;
 			}
 
 			chunk = chunk.next;

diff --git a/test/index.js b/test/index.js
@@ -845,24 +845,96 @@ describe( 'MagicString', function () {
 			assert.equal( s.slice( 0, -3 ), 'abcdefghi' );
 		});
 
+		it( 'includes inserted characters, respecting insertion direction', function () {
+			var s = new MagicString( 'abefij' );
+
+			s.insertRight( 2, 'cd' );
+			s.insertLeft( 4, 'gh' );
+
+			assert.equal( s.slice(), 'abcdefghij' );
+			assert.equal( s.slice( 1, 5 ), 'bcdefghi' );
+			assert.equal( s.slice( 2, 4 ), 'cdefgh' );
+			assert.equal( s.slice( 3, 4 ), 'fgh' );
+			assert.equal( s.slice( 0, 2 ), 'ab' );
+			assert.equal( s.slice( 0, 3 ), 'abcde' );
+			assert.equal( s.slice( 4, 6 ), 'ij' );
+			assert.equal( s.slice( 3, 6 ), 'fghij' );
+		});
+
+		it( 'supports characters moved outward', function () {
+			var s = new MagicString( 'abcdEFghIJklmn' );
+
+			s.move( 4, 6, 2 );
+			s.move( 8, 10, 12 );
+			assert.equal( s.toString(), 'abEFcdghklIJmn' );
+
+			assert.equal( s.slice( 1, -1 ), 'bEFcdghklIJm' );
+			assert.equal( s.slice( 2, -2 ), 'cdghkl' );
+			assert.equal( s.slice( 3, -3 ), 'dghk' );
+			assert.equal( s.slice( 4, -4 ), 'EFcdghklIJ' );
+			assert.equal( s.slice( 5, -5 ), 'FcdghklI' );
+			assert.equal( s.slice( 6, -6 ), 'gh' );
+		});
+
+		it( 'supports characters moved inward', function () {
+			var s = new MagicString( 'abCDefghijKLmn' );
+
+			s.move( 2, 4, 6 );
+			s.move( 10, 12, 8 );
+			assert.equal( s.toString(), 'abefCDghKLijmn' );
+
+			assert.equal( s.slice( 1, -1 ), 'befCDghKLijm' );
+			assert.equal( s.slice( 2, -2 ), 'CDghKL' );
+			assert.equal( s.slice( 3, -3 ), 'DghK' );
+			assert.equal( s.slice( 4, -4 ), 'efCDghKLij' );
+			assert.equal( s.slice( 5, -5 ), 'fCDghKLi' );
+			assert.equal( s.slice( 6, -6 ), 'gh' );
+		});
+
+		it( 'supports characters moved opposing', function () {
+			var s = new MagicString( 'abCDefghIJkl' );
+
+			s.move( 2, 4, 8 );
+			s.move( 8, 10, 4 );
+			assert.equal( s.toString(), 'abIJefghCDkl' );
+
+			assert.equal( s.slice( 1, -1 ), 'bIJefghCDk' );
+			assert.equal( s.slice( 2, -2 ), '' );
+			assert.equal( s.slice( 3, -3 ), '' );
+			assert.equal( s.slice( -3, 3 ), 'JefghC' );
+			assert.equal( s.slice( 4, -4 ), 'efgh' );
+			assert.equal( s.slice( 0, 3 ), 'abIJefghC' );
+			assert.equal( s.slice( 3 ), 'Dkl' );
+			assert.equal( s.slice( 0, -3 ), 'abI' );
+			assert.equal( s.slice( -3 ), 'JefghCDkl' );
+		});
+
 		it( 'errors if replaced characters are used as slice anchors', function () {
 			var s = new MagicString( 'abcdef' );
 			s.overwrite( 2, 4, 'CD' );
 
 			assert.throws( function () {
 				s.slice( 2, 3 );
-			}, /slice anchors/ );
+			}, /slice end anchor/ );
 
 			assert.throws( function () {
 				s.slice( 3, 4 );
-			}, /slice anchors/ );
+			}, /slice start anchor/ );
 
 			assert.throws( function () {
 				s.slice( 3, 5 );
-			}, /slice anchors/ );
+			}, /slice start anchor/ );
 
 			assert.equal( s.slice( 1, 5 ), 'bCDe' );
 		});
+
+		it( 'does not error if slice is after removed characters', function () {
+			var s = new MagicString( 'abcdef' );
+
+			s.remove( 0, 2 );
+
+			assert.equal( s.slice( 2, 4 ), 'cd' );
+		});
 	});
 
 	describe( 'snip', function () {