Support file-relative values via functions

CHANGELOG.md

@@ -1,5 +1,9 @@
 # rollup-plugin-replace changelog
 
+## 1.2.0
+
+* Allow replacement to be a function that takes a module ID ([#1](https://github.com/rollup/rollup-plugin-replace/issues/1))
+
 ## 1.1.0
 
 * Generate sourcemaps by default

README.md

@@ -58,6 +58,14 @@ rollup({
 }
 ```
 
+A replacement value can be supplied as a function that takes a module ID as its only argument:
+
+```js
+{
+  __dirname: ( id ) => `'${path.dirname( id )}'`
+}
+```
+
 
 ## License
 

package.json

@@ -1,8 +1,10 @@
 {
   "name": "rollup-plugin-replace",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "devDependencies": {
+    "babel-preset-es2015": "^6.3.13",
     "babel-preset-es2015-rollup": "^1.0.0",
+    "babel-register": "^6.3.13",
     "eslint": "^1.7.3",
     "mocha": "^2.3.3",
     "rollup": "^0.22.0",
@@ -16,7 +18,7 @@
     "rollup-pluginutils": "^1.1.0"
   },
   "scripts": {
-    "test": "mocha",
+    "test": "mocha --compilers js:babel-register",
     "pretest": "npm run build",
     "build": "rollup -c -f cjs -o dist/rollup-plugin-replace.cjs.js && rollup -c -f es6 -o dist/rollup-plugin-replace.es6.js",
     "prebuild": "rm -rf dist/*",

src/index.js

@@ -5,12 +5,39 @@ function escape ( str ) {
 	return str.replace( /[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g, '\\$&' );
 }
 
+function assign ( target, source ) {
+	Object.keys( source ).forEach( key => {
+		target[ key ] = source[ key ];
+	});
+	return target;
+}
+
+function functor ( thing ) {
+	if ( typeof thing === 'function' ) return thing;
+	return () => thing;
+}
+
 export default function replace ( options = {} ) {
-	const values = options.values || options;
+	const filter = createFilter( options.include, options.exclude );
 	const delimiters = ( options.delimiters || [ '', '' ] ).map( escape );
+
+	let values;
+
+	if ( options.values ) {
+		values = options.values;
+	} else {
+		values = assign( {}, options );
+		delete values.delimiters;
+		delete values.include;
+		delete values.exclude;
+	}
+
 	const pattern = new RegExp( delimiters[0] + '(' + Object.keys( values ).join( '|' ) + ')' + delimiters[1], 'g' );
 
-	const filter = createFilter( options.include, options.exclude );
+	// convert all values to functions
+	Object.keys( values ).forEach( key => {
+		values[ key ] = functor( values[ key ] );
+	});
 
 	return {
 		transform ( code, id ) {
@@ -27,7 +54,7 @@ export default function replace ( options = {} ) {
 
 				start = match.index;
 				end = start + match[0].length;
-				replacement = String( values[ match[1] ] );
+				replacement = String( values[ match[1] ]( id ) );
 
 				magicString.overwrite( start, end, replacement );
 			}

test/.babelrc

@@ -0,0 +1,3 @@
+{
+	"presets": [ "es2015" ]
+}

test/samples/relative/dir/foo.js

@@ -0,0 +1 @@
+export default __filename;

test/samples/relative/main.js

@@ -0,0 +1,5 @@
+import foo from './dir/foo.js';
+
+var bar = __filename;
+
+export { foo, bar };

test/test.js

@@ -0,0 +1,47 @@
+import * as assert from 'assert';
+import * as path from 'path';
+import { rollup } from 'rollup';
+import replace from '..';
+
+process.chdir( __dirname );
+
+describe( 'rollup-plugin-replace', () => {
+	it( 'replaces strings', () => {
+		return rollup({
+			entry: 'samples/basic/main.js',
+			plugins: [
+				replace({
+					ENV: "'production'"
+				})
+			]
+		}).then( bundle => {
+			const generated = bundle.generate();
+			const code = generated.code;
+
+			assert.ok( code.indexOf( "'production' !== 'production'" ) !== -1 );
+		});
+	});
+
+	it( 'allows replacement to be a function', () => {
+		return rollup({
+			entry: 'samples/relative/main.js',
+			plugins: [
+				replace({
+					__filename: id => `'${id.slice( path.resolve( __dirname, 'samples/relative' ).length + 1 )}'`
+				})
+			]
+		}).then( bundle => {
+			const generated = bundle.generate({ format: 'cjs' });
+			const code = generated.code;
+
+			const fn = new Function( 'module', 'exports', code );
+			const module = { exports: {} };
+			fn( module, module.exports );
+
+			assert.equal( module.exports.foo, 'dir/foo.js' );
+			assert.equal( module.exports.bar, 'main.js' );
+		});
+	});
+
+	// TODO tests for delimiters, sourcemaps, etc
+});