iterator.js - mozsearch

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// Ensure that we're using [[ArrayLength]] to determine the number of

// values to produce instead of the length property.

function testIterationCount(iterator, expectedLength) {

    for (let i = 0; i < expectedLength; i++)

        assertEq(iterator.next().done, false);

    assertEq(iterator.next().done, true);

let i8Array = new Int8Array(4);

Object.defineProperty(i8Array, "length", {value: 0});

let i8Iterator = i8Array[Symbol.iterator]();

testIterationCount(i8Iterator, 4);

// Veryify that the length property isn't even touched

i8Array = new Int8Array();

Object.defineProperty(i8Array, "length", {

    get() {

        throw TypeError;

});

i8Iterator = i8Array[Symbol.iterator]();

testIterationCount(i8Iterator, 0);

// Verify that it works for set as well

i8Array = new Uint8Array(1);

// Try setting a high length which would trigger failure

Object.defineProperty(i8Array, "length", {value: 15});

// Works if the fake length is ignored

(new Uint8Array(4)).set(i8Array, 3);

// Ensure that it works across globals

let g2 = newGlobal();

i8Array = new Int8Array(8);

Object.defineProperty(i8Array, "length", {value: 0});

let iterator = i8Array[Symbol.iterator]();

iterator.next = g2.Array.prototype[Symbol.iterator]().next;

testIterationCount(iterator, 8);

if (typeof reportCompare === "function")

    reportCompare(true, true);