Implements LRU cache. (Fixes #80)

index.js

@@ -6,56 +6,74 @@ var applySourceMap = require('vinyl-sourcemaps-apply');
 var objectAssign = require('object-assign');
 var replaceExt = require('replace-ext');
 var babel = require('babel-core');
+var lru = require('lru-cache');
+var crypto = require('crypto');
 
 function replaceExtension(fp) {
 	return path.extname(fp) ? replaceExt(fp, '.js') : fp;
 }
 
-module.exports = function (opts) {
-	opts = opts || {};
-
-	return through.obj(function (file, enc, cb) {
-		if (file.isNull()) {
-			cb(null, file);
-			return;
-		}
-
-		if (file.isStream()) {
-			cb(new gutil.PluginError('gulp-babel', 'Streaming not supported'));
-			return;
-		}
-
-		try {
-			var fileOpts = objectAssign({}, opts, {
-				filename: file.path,
-				filenameRelative: file.relative,
-				sourceMap: Boolean(file.sourceMap),
-				sourceFileName: file.relative,
-				sourceMapTarget: file.relative
-			});
-
-			var res = babel.transform(file.contents.toString(), fileOpts);
-
-			if (file.sourceMap && res.map) {
-				res.map.file = replaceExtension(res.map.file);
-				applySourceMap(file, res.map);
+module.exports = function (lruOptions) {
+	lruOptions = lruOptions || 500;
+
+	var cache = lru(lruOptions);
+
+	return function (opts) {
+		opts = opts || {};
+
+		return through.obj(function (file, enc, cb) {
+			if (file.isNull()) {
+				cb(null, file);
+				return;
 			}
 
-			if (!res.ignored) {
-				file.contents = new Buffer(res.code);
-				file.path = replaceExtension(file.path);
+			if (file.isStream()) {
+				cb(new gutil.PluginError('gulp-babel', 'Streaming not supported'));
+				return;
 			}
 
-			file.babel = res.metadata;
+			try {
+				var fileOpts = objectAssign({}, opts, {
+					filename: file.path,
+					filenameRelative: file.relative,
+					sourceMap: Boolean(file.sourceMap),
+					sourceFileName: file.relative,
+					sourceMapTarget: file.relative
+				});
+
+				var resultHash = crypto.createHash('sha1').update(file.contents.toString()).digest('hex');
+
+				var res;
+
+				res = cache.get(resultHash);
 
-			this.push(file);
-		} catch (err) {
-			this.emit('error', new gutil.PluginError('gulp-babel', err, {
-				fileName: file.path,
-				showProperties: false
-			}));
-		}
+				if (!res) {
+					res = babel.transform(file.contents.toString(), fileOpts);
+
+					cache.set(resultHash, res);
+				}
+
+				if (file.sourceMap && res.map) {
+					res.map.file = replaceExtension(res.map.file);
+					applySourceMap(file, res.map);
+				}
+
+				if (!res.ignored) {
+					file.contents = new Buffer(res.code);
+					file.path = replaceExtension(file.path);
+				}
+
+				file.babel = res.metadata;
+
+				this.push(file);
+			} catch (err) {
+				this.emit('error', new gutil.PluginError('gulp-babel', err, {
+					fileName: file.path,
+					showProperties: false
+				}));
+			}
 
-		cb();
-	});
+			cb();
+		});
+	};
 };

package.json

@@ -36,6 +36,7 @@
   "dependencies": {
     "babel-core": "^6.0.2",
     "gulp-util": "^3.0.0",
+    "lru-cache": "^4.0.0",
     "object-assign": "^4.0.1",
     "replace-ext": "0.0.1",
     "through2": "^2.0.0",

readme.md

@@ -30,12 +30,28 @@ gulp.task('default', () =>
 
 ## API
 
-### babel([options])
-
-#### options
-
-See the Babel [options](https://babeljs.io/docs/usage/options/), except for `sourceMap` and `filename` which is handled for you.
-
+```js
+const createBabel = require('gulp-babel');
+
+/**
+ * @see https://github.com/isaacs/node-lru-cache#options
+ */
+type lruOptions = {
+	max: ?number,
+	length: ?Function,
+	dispose: ?Function,
+	maxAge: ?number
+};
+
+/**
+ * @see See the Babel options (https://babeljs.io/docs/usage/options/), except for `sourceMap` and `filename` which is handled for you.
+ */
+type babelOptions = {};
+
+const babel = createBabel({max: 500}: lruOptions);
+
+babel({}: babelOptions);
+```
 
 ## Source Maps
 
@@ -44,9 +60,11 @@ Use [gulp-sourcemaps](https://github.com/floridoo/gulp-sourcemaps) like this:
 ```js
 const gulp = require('gulp');
 const sourcemaps = require('gulp-sourcemaps');
-const babel = require('gulp-babel');
+const createBabel = require('gulp-babel');
 const concat = require('gulp-concat');
 
+const babel = createBabel();
+
 gulp.task('default', () =>
 	gulp.src('src/**/*.js')
 		.pipe(sourcemaps.init())
@@ -59,7 +77,6 @@ gulp.task('default', () =>
 );
 ```
 
-
 ## Babel Metadata
 
 Files in the stream are annotated with a `babel` property, which contains the metadata from [`babel.transform()`](https://babeljs.io/docs/usage/api/).
@@ -68,9 +85,11 @@ Files in the stream are annotated with a `babel` property, which contains the me
 
 ```js
 const gulp = require('gulp');
-const babel = require('gulp-babel');
+const createBabel = require('gulp-babel');
 const through = require('through2');
 
+const babel = createBabel();
+
 function logFileHelpers() {
 	return through.obj((file, enc, cb) => {
 		console.log(file.babel.usedHelpers);
@@ -102,7 +121,9 @@ Use it as plugin:
 
 ```js
 const gulp = require('gulp');
-const babel = require('gulp-babel');
+const createBabel = require('gulp-babel');
+
+const babel = createBabel();
 
 gulp.task('default', () =>
 	gulp.src('src/app.js')