JavaScriptCore-7601.1.46.3.tar.gz

[apple/javascriptcore.git] / builtins / ArrayConstructor.js

diff --git a/builtins/ArrayConstructor.js b/builtins/ArrayConstructor.js
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+++ b/builtins/ArrayConstructor.js
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+/*
+ * Copyright (C) 2015 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+function of(/* items... */)
+{
+    "use strict";
+
+    var length = arguments.length;
+    // TODO: Need isConstructor(this) instead of typeof "function" check.
+    var array = typeof this === 'function' ? new this(length) : new @Array(length);
+    for (var k = 0; k < length; ++k)
+        @putByValDirect(array, k, arguments[k]);
+    array.length = length;
+    return array;
+}
+
+function from(items /*, mapFn, thisArg */) {
+    "use strict";
+
+    var thisObj = this;
+
+    var mapFn = arguments.length > 1 ? arguments[1] : undefined;
+
+    var thisArg;
+
+    if (mapFn !== undefined) {
+        if (typeof mapFn !== "function")
+            throw new @TypeError("Array.from requires that the second argument, when provided, be a function");
+
+        if (arguments.length > 2)
+            thisArg = arguments[2];
+    }
+
+    if (items == null)
+        throw new @TypeError("Array.from requires an array-like object - not null or undefined");
+
+    var iteratorMethod = items[@symbolIterator];
+    if (iteratorMethod != null) {
+        if (typeof iteratorMethod !== "function")
+            throw new @TypeError("Array.from requires that the property of the first argument, items[Symbol.iterator], when exists, be a function");
+
+        // TODO: Need isConstructor(thisObj) instead of typeof "function" check.
+        var result = (typeof thisObj === "function") ? @Object(new thisObj()) : [];
+
+        var k = 0;
+        var iterator = iteratorMethod.@call(items);
+
+        // Since for-of loop once more looks up the @@iterator property of a given iterable,
+        // it could be observable if the user defines a getter for @@iterator.
+        // To avoid this situation, we define a wrapper object that @@iterator just returns a given iterator.
+        var wrapper = {
+            [@symbolIterator]() {
+                return iterator;
+            }
+        };
+
+        for (var value of wrapper) {
+            if (mapFn)
+                @putByValDirect(result, k, thisArg === undefined ? mapFn(value, k) : mapFn.@call(thisArg, value, k));
+            else
+                @putByValDirect(result, k, value);
+            k += 1;
+        }
+
+        result.length = k;
+        return result;
+    }
+
+    var arrayLike = @Object(items);
+    var arrayLikeLength = @toLength(arrayLike.length);
+
+    // TODO: Need isConstructor(thisObj) instead of typeof "function" check.
+    var result = (typeof thisObj === "function") ? @Object(new thisObj(arrayLikeLength)) : new @Array(arrayLikeLength);
+
+    var k = 0;
+    while (k < arrayLikeLength) {
+        var value = arrayLike[k];
+        if (mapFn)
+            @putByValDirect(result, k, thisArg === undefined ? mapFn(value, k) : mapFn.@call(thisArg, value, k));
+        else
+            @putByValDirect(result, k, value);
+        k += 1;
+    }
+
+    result.length = arrayLikeLength;
+    return result;
+}