Bug 1321509 - remove references to Array.slice in addon-sdk util/object;r=zer0
authorJulian Descottes <jdescottes@mozilla.com>
Wed, 07 Dec 2016 18:03:32 +0100
changeset 325353 d72c318a4f42ab4d4e34d27be6a590fc5df619b9
parent 325352 61d6fe7c63903f8f3d5ba8e9af58f6893f763167
child 325354 b9b90a3362eaed6b77720905182ad4153d8b1dab
push id24
push usermaklebus@msu.edu
push dateTue, 20 Dec 2016 03:11:33 +0000
reviewerszer0
bugs1321509
milestone53.0a1
Bug 1321509 - remove references to Array.slice in addon-sdk util/object;r=zer0 MozReview-Commit-ID: 8HCwdqy4kwl
addon-sdk/source/lib/sdk/util/object.js
--- a/addon-sdk/source/lib/sdk/util/object.js
+++ b/addon-sdk/source/lib/sdk/util/object.js
@@ -4,16 +4,20 @@
 "use strict";
 
 module.metadata = {
   "stability": "unstable"
 };
 
 const { flatten } = require('./array');
 
+// Create a shortcut for Array.prototype.slice.call().
+const unbind = Function.call.bind(Function.bind, Function.call);
+const slice = unbind(Array.prototype.slice);
+
 /**
  * Merges all the properties of all arguments into first argument. If two or
  * more argument objects have own properties with the same name, the property
  * is overridden, with precedence from right to left, implying, that properties
  * of the object on the left are overridden by a same named property of the
  * object on the right.
  *
  * Any argument given with "falsy" value - commonly `null` and `undefined` in
@@ -29,33 +33,33 @@ const { flatten } = require('./array');
  *    b.name    // 'b'
  */
 function merge(source) {
   let descriptor = {};
 
   // `Boolean` converts the first parameter to a boolean value. Any object is
   // converted to `true` where `null` and `undefined` becames `false`. Therefore
   // the `filter` method will keep only objects that are defined and not null.
-  Array.slice(arguments, 1).filter(Boolean).forEach(function onEach(properties) {
+  slice(arguments, 1).filter(Boolean).forEach(function onEach(properties) {
     getOwnPropertyIdentifiers(properties).forEach(function(name) {
       descriptor[name] = Object.getOwnPropertyDescriptor(properties, name);
     });
   });
   return Object.defineProperties(source, descriptor);
 }
 exports.merge = merge;
 
 /**
  * Returns an object that inherits from the first argument and contains all the
  * properties from all following arguments.
  * `extend(source1, source2, source3)` is equivalent of
  * `merge(Object.create(source1), source2, source3)`.
  */
 function extend(source) {
-  let rest = Array.slice(arguments, 1);
+  let rest = slice(arguments, 1);
   rest.unshift(Object.create(source));
   return merge.apply(null, rest);
 }
 exports.extend = extend;
 
 function has(obj, key) {
   return obj.hasOwnProperty(key);
 }
@@ -67,17 +71,17 @@ function each(obj, fn) {
 exports.each = each;
 
 /**
  * Like `merge`, except no property descriptors are manipulated, for use
  * with platform objects. Identical to underscore's `extend`. Useful for
  * merging XPCOM objects
  */
 function safeMerge(source) {
-  Array.slice(arguments, 1).forEach(function onEach (obj) {
+  slice(arguments, 1).forEach(function onEach (obj) {
     for (let prop in obj) source[prop] = obj[prop];
   });
   return source;
 }
 exports.safeMerge = safeMerge;
 
 /*
  * Returns a copy of the object without omitted properties