Implements LRU cache.

index.js

@@ -6,14 +6,20 @@ 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) {
+module.exports = function (opts, lruOptions) {
 	opts = opts || {};
 
+	lruOptions = lruOptions || 500;
+
+	var cache = lru(lruOptions);
+
 	return through.obj(function (file, enc, cb) {
 		if (file.isNull()) {
 			cb(null, file);
@@ -34,7 +40,17 @@ module.exports = function (opts) {
 				sourceMapTarget: file.relative
 			});
 
-			var res = babel.transform(file.contents.toString(), fileOpts);
+			var resultHash = crypto.createHash('sha1').update(file.contents.toString()).digest('hex');
+
+			var res;
+
+			res = cache.get(resultHash);
+
+			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);

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 +30,15 @@ gulp.task('default', () =>
 
 ## API
 
-### babel([options])
+### babel([babelOptions][, lruCacheOptions = 500])
 
-#### options
+#### babelOptions
 
 See the Babel [options](https://babeljs.io/docs/usage/options/), except for `sourceMap` and `filename` which is handled for you.
 
+#### lruCacheOptions
+
+See [`lru-cache` options](https://github.com/isaacs/node-lru-cache#options).
 
 ## Source Maps
 
@@ -59,7 +62,6 @@ 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/).