populate map.sourcesContent with original code

src/Bundle.js

@@ -115,9 +115,9 @@ export default class Bundle {
 		return Promise.resolve( this.load( id, this.loadOptions ) )
 			.then( source => transform( source, id, this.transformers ) )
 			.then( source => {
-				const { code, ast, sourceMapChain } = source;
+				const { code, originalCode, ast, sourceMapChain } = source;
 
-				const module = new Module({ id, code, ast, sourceMapChain, bundle: this });
+				const module = new Module({ id, code, originalCode, ast, sourceMapChain, bundle: this });
 
 				this.modules.push( module );
 				this.moduleById[ id ] = module;

src/Module.js

@@ -128,8 +128,9 @@ class SyntheticNamespaceDeclaration {
 }
 
 export default class Module {
-	constructor ({ id, code, ast, sourceMapChain, bundle }) {
+	constructor ({ id, code, originalCode, ast, sourceMapChain, bundle }) {
 		this.code = code;
+		this.originalCode = originalCode;
 		this.sourceMapChain = sourceMapChain;
 
 		this.bundle = bundle;

src/utils/collapseSourcemaps.js

@@ -63,6 +63,7 @@ export default function collapseSourcemaps ( map, modules ) {
 		return tracedLine;
 	});
 
+	map.sourcesContent = modules.map( module => module.originalCode );
 	map.mappings = encode( tracedMappings );
 	return map;
 }

src/utils/transform.js

@@ -8,6 +8,7 @@ export default function transform ( source, id, transformers ) {
 		};
 	}
 
+	let originalCode = source.code;
 	let ast = source.ast;
 
 	let code = transformers.reduce( ( previous, transformer ) => {
@@ -29,5 +30,5 @@ export default function transform ( source, id, transformers ) {
 		return result.code;
 	}, source.code );
 
-	return { code, ast, sourceMapChain };
+	return { code, originalCode, ast, sourceMapChain };
 }