ArrayIterator.prototype.js   [plain text]

/*
 * Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>.
 *
 * 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 next() {
    "use strict";

    if (this == null)
        throw new @TypeError("%ArrayIteratorPrototype%.next requires that |this| not be null or undefined");

    var itemKind = this.@arrayIterationKind;
    if (itemKind === undefined)
        throw new @TypeError("%ArrayIteratorPrototype%.next requires that |this| be an Array Iterator instance");

    var done = true;
    var value = undefined;

    var array = this.@iteratedObject;
    if (array !== undefined) {
        var index = this.@arrayIteratorNextIndex;
        var length = array.length >>> 0;
        if (index >= length) {
            this.@iteratedObject = undefined;
        } else {
            this.@arrayIteratorNextIndex = index + 1;
            done = false;
            if (itemKind === @arrayIterationKindKey) {
                value = index;
            } else if (itemKind === @arrayIterationKindValue) {
                value = array[index];
            } else {
                value = [ index, array[index] ];
            }
        }
    }

    return {done, value};
}