Breaking: Avoid mutating options when defaulted (closes #16)

Author: phated

index.js

@@ -1,6 +1,7 @@
 'use strict';
 
 var File = require('vinyl');
+var defaults = require('object.defaults');
 
 var helpers = require('./lib/helpers');
 
@@ -77,14 +78,11 @@ function write(file, options, callback) {
 		return callback(null, file);
 	}
 
-	// TODO: don't mutate - needs test too
-	// set defaults for options if unset
-	if (options.includeContent === undefined) {
-		options.includeContent = true;
-	}
-	if (options.addComment === undefined) {
-		options.addComment = true;
-	}
+	// Set defaults for options if unset
+	var opts = defaults({}, options, {
+		includeContent: true,
+		addComment: true,
+	});
 
 	var sourceMap = file.sourceMap;
 
@@ -113,12 +111,12 @@ function write(file, options, callback) {
 	}
 
 	var state = {
-		destPath: options.path,
+		destPath: opts.path,
 		sourceMap: sourceMap,
 		sourceMapFile: null,
 	};
 
-	helpers.writeSourceMaps(file, state, options, callback);
+	helpers.writeSourceMaps(file, state, opts, callback);
 }
 
 module.exports = {

package.json

@@ -28,6 +28,7 @@
     "css": "^2.2.1",
     "detect-newline": "^2.1.0",
     "graceful-fs": "^4.1.6",
+    "object.defaults": "^1.0.0",
     "source-map": "^0.5.6",
     "strip-bom": "^2.0.0",
     "through2": "^2.0.1",

test/add.js

@@ -81,6 +81,19 @@ describe('add', function() {
 
 	describe('ensures options argument', function() {
 
+		// Currently no options are defaulted
+		// TODO: Enable test if any options are defaulted
+		it.skip('is not mutated', function(done) {
+			var defaultedOpts = {};
+
+			var opts = {};
+
+			var file = makeFile();
+			sourcemaps.add(file, opts, function(err) {
+				expect(opts).toNotEqual(defaultedOpts);
+				done(err);
+			});
+		});
 
 		it('is defaulted if undefined', function(done) {
 			var file = makeFile();

test/write.js

@@ -92,6 +92,21 @@ describe('write', function() {
 
 	describe('ensures options argument', function() {
 
+		it('is not mutated', function(done) {
+			var defaultedOpts = {
+				includeContent: true,
+				addComment: true,
+			};
+
+			var opts = {};
+
+			var file = makeFile();
+			sourcemaps.write(file, opts, function(err) {
+				expect(opts).toNotEqual(defaultedOpts);
+				done(err);
+			});
+		});
+
 		it('is defaulted if undefined', function(done) {
 			var file = makeFile();
 			sourcemaps.write(file, undefined, function(err) {