collapse sourcemaps from bundle transformers

src/Bundle.js

@@ -12,7 +12,8 @@ import getIndentString from './utils/getIndentString.js';
 import { unixizePath } from './utils/normalizePlatform.js';
 import transform from './utils/transform.js';
 import transformBundle from './utils/transformBundle.js';
-import collapseSourcemaps from './utils/collapseSourcemaps.js';
+import collapseSourcemaps from './utils/sourcemap/collapseSourcemaps.js';
+import SOURCEMAPPING_URL from './utils/sourcemap/sourceMappingURL.js';
 import callIfFunction from './utils/callIfFunction.js';
 import { isRelative } from './utils/path.js';
 
@@ -247,22 +248,25 @@ export default class Bundle {
 		if ( banner ) magicString.prepend( banner + '\n' );
 		if ( footer ) magicString.append( '\n' + footer );
 
-		const code = magicString.toString();
+		let code = magicString.toString();
 		let map = null;
+		let bundleSourcemapChain = [];
+
+		code = transformBundle( code, this.bundleTransformers, bundleSourcemapChain )
+			.replace( new RegExp( `\\/\\/#\\s+${SOURCEMAPPING_URL}=.+\\n?`, 'g' ), '' );
 
 		if ( options.sourceMap ) {
 			const file = options.sourceMapFile || options.dest;
-			map = magicString.generateMap({
-				includeContent: true,
-				file
-				// TODO
-			});
+			map = magicString.generateMap({ file, includeContent: true });
+
+			if ( this.transformers.length || this.bundleTransformers.length ) {
+				map = collapseSourcemaps( map, usedModules, bundleSourcemapChain );
+			}
 
-			if ( this.transformers.length ) map = collapseSourcemaps( map, usedModules );
 			map.sources = map.sources.map( unixizePath );
 		}
 
-		return transformBundle( { code, map }, this.bundleTransformers );
+		return { code, map };
 	}
 
 	sort () {

src/Module.js

@@ -6,7 +6,7 @@ import { blank, keys } from './utils/object.js';
 import { basename, extname } from './utils/path.js';
 import getLocation from './utils/getLocation.js';
 import makeLegalIdentifier from './utils/makeLegalIdentifier.js';
-import SOURCEMAPPING_URL from './utils/sourceMappingURL.js';
+import SOURCEMAPPING_URL from './utils/sourcemap/sourceMappingURL.js';
 import { SyntheticDefaultDeclaration, SyntheticNamespaceDeclaration } from './Declaration.js';
 import { isFalsy, isTruthy } from './ast/conditions.js';
 import { emptyBlockStatement } from './ast/create.js';

src/rollup.js

@@ -3,7 +3,7 @@ import { basename } from './utils/path.js';
 import { writeFile } from './utils/fs.js';
 import { keys } from './utils/object.js';
 import validateKeys from './utils/validateKeys.js';
-import SOURCEMAPPING_URL from './utils/sourceMappingURL.js';
+import SOURCEMAPPING_URL from './utils/sourcemap/sourceMappingURL.js';
 import Bundle from './Bundle.js';
 
 export const VERSION = '<@VERSION@>';

src/utils/collapseSourcemaps.js

@@ -1,72 +0,0 @@
-import { encode, decode } from 'sourcemap-codec';
-
-function traceSegment ( loc, mappings ) {
-	const line = loc[0];
-	const column = loc[1];
-
-	const segments = mappings[ line ];
-
-	if ( !segments ) return null;
-
-	for ( let i = 0; i < segments.length; i += 1 ) {
-		const segment = segments[i];
-
-		if ( segment[0] > column ) return null;
-
-		if ( segment[0] === column ) {
-			if ( segment[1] !== 0 ) {
-				throw new Error( 'Bad sourcemap' );
-			}
-
-			return [ segment[2], segment[3] ];
-		}
-	}
-
-	return null;
-}
-
-export default function collapseSourcemaps ( map, modules ) {
-	const chains = modules.map( module => {
-		return module.sourceMapChain.map( map => {
-			if ( !map ) throw new Error( 'Cannot generate a sourcemap if non-sourcemap-generating transformers are used' );
-			return decode( map.mappings );
-		});
-	});
-
-	const decodedMappings = decode( map.mappings );
-
-	const tracedMappings = decodedMappings.map( line => {
-		let tracedLine = [];
-
-		line.forEach( segment => {
-			const sourceIndex = segment[1];
-			const sourceCodeLine = segment[2];
-			const sourceCodeColumn = segment[3];
-
-			const chain = chains[ sourceIndex ];
-
-			let i = chain.length;
-			let traced = [ sourceCodeLine, sourceCodeColumn ];
-
-			while ( i-- && traced ) {
-				traced = traceSegment( traced, chain[i] );
-			}
-
-			if ( traced ) {
-				tracedLine.push([
-					segment[0],
-					segment[1],
-					traced[0],
-					traced[1]
-					// TODO name?
-				]);
-			}
-		});
-
-		return tracedLine;
-	});
-
-	map.sourcesContent = modules.map( module => module.originalCode );
-	map.mappings = encode( tracedMappings );
-	return map;
-}

src/utils/sourcemap/collapseSourcemaps.js

@@ -0,0 +1,87 @@
+import { encode, decode } from 'sourcemap-codec';
+
+function Source ( map, sources ) {
+	if ( !map ) throw new Error( 'Cannot generate a sourcemap if non-sourcemap-generating transformers are used' );
+
+	this.sources = sources;
+	this.names = map.names;
+	this.mappings = decode( map.mappings );
+}
+
+Source.prototype = { // TODO bring into line with others post-https://github.com/rollup/rollup/pull/386
+	traceMappings () {
+		return this.mappings.map( line => {
+			let tracedLine = [];
+
+			line.forEach( segment => {
+				const source = this.sources[ segment[1] ];
+
+				const sourceCodeLine = segment[2];
+				const sourceCodeColumn = segment[3];
+
+				const traced = source.traceSegment( sourceCodeLine, sourceCodeColumn );
+
+				if ( traced ) {
+					tracedLine.push([
+						segment[0],
+						traced.index,
+						traced.line,
+						traced.column
+						// TODO name?
+					]);
+				}
+			});
+
+			return tracedLine;
+		});
+	},
+
+	traceSegment ( line, column ) {
+		const segments = this.mappings[ line ];
+
+		if ( !segments ) return null;
+
+		for ( let i = 0; i < segments.length; i += 1 ) {
+			const segment = segments[i];
+
+			if ( segment[0] > column ) return null;
+
+			if ( segment[0] === column ) {
+				const source = this.sources[ segment[1] ];
+
+				if ( !source ) throw new Error( 'Bad sourcemap' );
+
+				if ( source.isOriginal ) {
+					return { index: source.index, line: segment[2], column: segment[3] };
+				}
+
+				return source.traceSegment( segment[2], segment[3] );
+			}
+		}
+
+		return null;
+	}
+};
+
+export default function collapseSourcemaps ( map, modules, bundleSourcemapChain ) {
+	const sources = modules.map( ( module, i ) => {
+		let source = { isOriginal: true, index: i };
+
+		module.sourceMapChain.forEach( map => {
+			source = new Source( map, [ source ]);
+		});
+
+		return source;
+	});
+
+	let source = new Source( map, sources );
+
+	bundleSourcemapChain.forEach( map => {
+		source = new Source( map, [ source ] );
+	});
+
+	// we re-use the `map` object because it has convenient toString/toURL methods
+	map.sourcesContent = modules.map( module => module.originalCode );
+	map.mappings = encode( source.traceMappings() );
+	return map;
+}

src/utils/sourcemap/removeSourceMappingURL.js

@@ -0,0 +1,3 @@
+export default function removeSourceMappingURL ( code ) {
+	
+}

src/utils/transformBundle.js

@@ -1,17 +1,8 @@
-import MagicString from 'magic-string';
+export default function transformBundle ( code, transformers, sourceMapChain ) {
+	return transformers.reduce( ( code, transformer ) => {
+		let result = transformer( code );
 
-export default function transformBundle ( source, transformers ) {
-	if ( typeof source === 'string' ) {
-		source = {
-			code: source,
-			map: null
-		};
-	}
-
-	return transformers.reduce( ( previous, transformer ) => {
-		let result = transformer( previous.code, previous.map );
-
-		if ( result == null ) return previous;
+		if ( result == null ) return code;
 
 		if ( typeof result === 'string' ) {
 			result = {
@@ -19,21 +10,10 @@ export default function transformBundle ( source, transformers ) {
 				map: null
 			};
 		}
-		// `result.map` can only be a string if `result` isn't
-		else if ( typeof result.map === 'string' ) {
-			result.map = JSON.parse( result.map );
-		}
 
-		if (result.map != null) {
-			let map = new MagicString.Bundle().generateMap({});
-			map.file = result.map.file;
-			map.sources = result.map.sources;
-			map.sourcesContent = result.map.sourcesContent;
-			map.names = result.map.names;
-			map.mappings = result.map.mappings;
-			result.map = map;
-		}
+		const map = typeof result.map === 'string' ? JSON.parse( result.map ) : map;
+		sourceMapChain.push( map );
 
-		return result;
-	}, source );
+		return result.code;
+	}, code );
 }

test/sourcemaps/transform-bundle/_config.js

@@ -9,21 +9,13 @@ module.exports = {
 	options: {
 		plugins: [
 			{
-				transformBundle: function ( code, map ) {
-					var options = { fromString: true };
+				transformBundle: function ( code ) {
+					var options = {
+						fromString: true,
+						outSourceMap: 'x' // trigger sourcemap generation
+					};
 
-					if ( map != null ) {
-						options.inSourceMap = map;
-						options.outSourceMap = "out";
-					}
-
-					var result = uglify.minify( code, options );
-
-					if ( map != null ) {
-						result.code = result.code.slice( 0, -25 );
-					}
-
-					return result;
+					return uglify.minify( code, options );
 				}
 			}
 		]