From 2929f1a771bf24fbcea3bccd89d4c084323cee2c Mon Sep 17 00:00:00 2001
From: Rich-Harris <richard.a.harris@gmail.com>
Date: Sun, 9 Oct 2016 12:25:08 -0400
Subject: [PATCH] support function moduleContext option

---
 browser/path.js                 |  6 ------
 src/Bundle.js                   | 35 ++++++++++-----------------------
 src/Module.js                   |  1 +
 src/ast/nodes/ThisExpression.js | 19 +-----------------
 src/utils/path.js               |  2 +-
 5 files changed, 13 insertions(+), 50 deletions(-)

diff --git a/browser/path.js b/browser/path.js
index 84efd9d..279ba66 100644
--- a/browser/path.js
+++ b/browser/path.js
@@ -78,9 +78,3 @@ export function resolve ( ...paths ) {
 
 	return resolvedParts.join( '/' ); // TODO windows...
 }
-
-export function join ( ...parts ) {
-	const separator = '/';
-	const replaceExp = new RegExp(separator+'{1,}', 'g');
-	return parts.join(separator).replace(replaceExp, separator);
-}
diff --git a/src/Bundle.js b/src/Bundle.js
index 7b06181..66deba6 100644
--- a/src/Bundle.js
+++ b/src/Bundle.js
@@ -72,32 +72,17 @@ export default class Bundle {
 		this.externalModules = [];
 
 		this.context = String( options.context );
-		if (options.moduleContext) {
-			if (typeof options.moduleContext === 'object') {
-				const moduleContext = {};
-				for (const key in options.moduleContext) {
-					let resolvedKey;
-					if (isAbsolute(key)) {
-						resolvedKey = normalize(key);
-					} else {
-						const useWorkingDir = key.substring(0, 2) === `./` ? true : false;
-						let absoluteKey;
-						if (useWorkingDir) {
-							absoluteKey = join(process.cwd(), key.substring(2));
-						} else {
-							absoluteKey = join(dirname(options.entry), key);
-						}
-
-						resolvedKey = normalize(absoluteKey);
-					}
-						
-					moduleContext[resolvedKey] = options.moduleContext[key];
-				}
 
-				this.moduleContext = moduleContext;
-			} else {
-				throw new Error('options.moduleContext must be an object');
-			}
+		if ( typeof options.moduleContext === 'function' ) {
+			this.getModuleContext = id => options.moduleContext( id ) || this.context;
+		} else if ( typeof options.moduleContext === 'object' ) {
+			const moduleContext = new Map();
+			Object.keys( options.moduleContext ).forEach( key => {
+				moduleContext.set( resolve( key ), options.moduleContext[ key ] );
+			});
+			this.getModuleContext = id => moduleContext.get( id ) || this.context;
+		} else {
+			this.getModuleContext = () => this.context;
 		}
 
 		if ( typeof options.external === 'function' ) {
diff --git a/src/Module.js b/src/Module.js
index 3abdd4c..0cb02db 100644
--- a/src/Module.js
+++ b/src/Module.js
@@ -46,6 +46,7 @@ export default class Module {
 		this.bundle = bundle;
 		this.id = id;
 		this.excludeFromSourcemap = /\0/.test( id );
+		this.context = bundle.getModuleContext( id );
 
 		// all dependencies
 		this.sources = [];
diff --git a/src/ast/nodes/ThisExpression.js b/src/ast/nodes/ThisExpression.js
index b6b8f68..5d295fe 100644
--- a/src/ast/nodes/ThisExpression.js
+++ b/src/ast/nodes/ThisExpression.js
@@ -1,29 +1,12 @@
 import Node from '../Node.js';
 import {normalize} from '../../utils/path';
 
-function getContext (module) {
-	let context = module.bundle.context;
-	const moduleContext = module.bundle.moduleContext;
-	if (moduleContext) {
-		const moduleId = normalize(module.id);
-		const candidates = Object.keys(moduleContext)
-			.map(relPath => moduleId.indexOf(relPath) >= 0 ? moduleContext[relPath] : undefined)
-			.filter(context => !!context);
-
-		if (candidates.length) {
-			context = String( candidates[candidates.length - 1] );
-		} 
-	}
-
-	return context;
-}
-
 export default class ThisExpression extends Node {
 	initialise ( scope ) {
 		const lexicalBoundary = scope.findLexicalBoundary();
 
 		if ( lexicalBoundary.isModuleScope ) {
-			this.alias = getContext(this.module);
+			this.alias = this.module.context;
 			if ( this.alias === 'undefined' ) {
 				this.module.bundle.onwarn( 'The `this` keyword is equivalent to `undefined` at the top level of an ES module, and has been rewritten' );
 			}
diff --git a/src/utils/path.js b/src/utils/path.js
index 1f8af19..d2ce64d 100644
--- a/src/utils/path.js
+++ b/src/utils/path.js
@@ -13,4 +13,4 @@ export function normalize ( path ) {
 	return path.replace( /\\/g, '/' );
 }
 
-export { basename, dirname, extname, relative, resolve, join} from 'path';
+export { basename, dirname, extname, relative, resolve } from 'path';