Revert "Use ES.ArraySpeciesCreate properly." and "Overwrite `Array#sl…

…ice` so that it supports Array subclasses."

This reverts commits b5731c5505fdae884f6d78ce41928b7307f2b39f6 and dd9804ddede0515b34646959d409c3c7a259e61.

Fixes #322

es6-shim.js

@@ -85,7 +85,6 @@
   var _hasOwnProperty = Function.call.bind(Object.prototype.hasOwnProperty);
   var ArrayIterator; // make our implementation private
   var noop = function () {};
-  var arraySlice = Array.prototype.slice;
 
   var Symbol = globals.Symbol || {};
   var symbolSpecies = Symbol.species || '@@species';
@@ -318,28 +317,6 @@
       return result;
     },
 
-    ArraySpeciesCreate: function (originalArray, length) {
-      if (!Number.isInteger(length) || length < 0) {
-        throw new TypeError('length must be 0 or greater');
-      }
-      var len = length === 0 ? 0 : length; // eliminate negative zero
-      var C;
-      var isArray = Array.isArray(originalArray);
-      if (isArray) {
-        C = originalArray.constructor;
-        if (ES.TypeIsObject(C)) {
-          C = C[symbolSpecies];
-          if (C === null) {
-            C = undefined;
-          }
-        }
-      }
-      if (typeof C === 'undefined') {
-        return new Array(len);
-      }
-      return ES.Construct(C, len);
-    },
-
     Construct: function (C, args) {
       // CreateFromConstructor
       var obj;
@@ -1000,34 +977,6 @@
   }
   defineProperties(Array.prototype, ArrayPrototypeShims);
 
-  var Empty = function Empty() {};
-  if (!(Array.prototype.slice.call(new Empty()) instanceof Empty)) {
-    defineProperty(Array.prototype, 'slice', function slice(start, end) {
-      if (this instanceof Array || isArguments(this)) {
-        return arraySlice.apply(this, arguments);
-      }
-      var O = ES.ToObject(this);
-      var len = ES.ToLength(this.length);
-      var relativeStart = ES.ToInteger(start);
-      var k = relativeStart < 0 ? Math.max(len + relativeStart, 0) : Math.min(relativeStart, len);
-      var relativeEnd = typeof end === 'undefined' ? len : ES.ToInteger(end);
-      var finalEnd = relativeEnd < 0 ? Math.max(len + relativeEnd, 0) : Math.min(relativeEnd, len);
-      var count = Math.max(finalEnd - k, 0);
-      var A = ES.ArraySpeciesCreate(O, count);
-      var n = 0;
-      while (k < finalEnd) {
-        if (_hasOwnProperty(O, k)) {
-          A[n] = O[k];
-        }
-        k += 1;
-        n += 1;
-      }
-      A.length = n;
-      return A;
-    }, true);
-    Value.preserveToString(Array.prototype.slice, arraySlice);
-  }
-
   addIterator(Array.prototype, function () { return this.values(); });
   // Chrome defines keys/values/entries on Array, but doesn't give us
   // any way to identify its iterator.  So add our own shimmed field.

test/array.js

@@ -5,7 +5,6 @@ var runArrayTests = function () {
   'use strict';
 
   var Sym = typeof Symbol !== 'undefined' ? Symbol : {};
-  var symbolSpecies = Sym.species || '@@species';
   var isSymbol = function (sym) {
     /*jshint notypeof: true */
     return typeof Sym === 'function' && typeof sym === 'symbol';
@@ -22,43 +21,6 @@ var runArrayTests = function () {
       expect(exported.Array).to.equal(Array);
     });
 
-    var assertArrayLike = function (a, array) {
-      expect(a.length).to.equal(array.length);
-      expect(Array.from(a)).to.eql(array);
-    };
-
-    describe('#slice()', function () {
-      var C;
-      beforeEach(function () {
-        C = function C() {
-          var arr = Array.apply(this, arguments);
-          Object.assign(this, arr);
-          this.length = arr.length;
-        };
-        C[symbolSpecies] = C;
-      });
-
-      it('works on non-Arrays', function () {
-        var c = new C(1, 2, 3, 4);
-        assertArrayLike(c, [1, 2, 3, 4]);
-        expect(c).to.be.an.instanceOf(C);
-        var c2 = Array.prototype.slice.call(c, 1, -1);
-        assertArrayLike(c2, [2, 3]);
-        expect(c2).to.be.an.instanceOf(Array);
-      });
-
-      it('works on Arrays', function () {
-        C.prototype = Array.prototype;
-        var c = new C(1, 2, 3, 4);
-        assertArrayLike(c, [1, 2, 3, 4]);
-        expect(c).to.be.an.instanceOf(C);
-        expect(Array.isArray(c)).to.equal(true);
-        var c2 = Array.prototype.slice.call(c, 1, -1);
-        assertArrayLike(c2, [2, 3]);
-        expect(c2).to.be.an.instanceOf(C);
-      });
-    });
-
     describe('@@iterator', function () {
       it('uses Symbol.iterator if available', function () {
         var a = [];