findLast-and-findLastIndex.js

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/*

 * Any copyright is dedicated to the Public Domain.

 * https://creativecommons.org/publicdomain/zero/1.0/

*/

var BUGNUMBER = 1704385;

var summary = "Implement %TypedArray%.prototype.{findLast, findLastIndex}";

print(BUGNUMBER + ": " + summary);

const methods = ["findLast", "findLastIndex"];

anyTypedArrayConstructors.forEach(constructor => {

    methods.forEach(method => {

        var arr = new constructor([0, 1, 2, 3, 4, 5]);

        // test that this.length is never called

        Object.defineProperty(arr, "length", {

            get() {

                throw new Error("length accessor called");

});

        assertEq(arr[method].length, 1);

        assertEq(arr[method](v => v === 3), 3);

        assertEq(arr[method](v => v === 6), method === "findLast" ? undefined : -1);

        var thisValues = [undefined, null, true, 1, "foo", [], {}];

        if (typeof Symbol == "function")

            thisValues.push(Symbol());

        thisValues.forEach(thisArg =>

            assertThrowsInstanceOf(() => arr[method].call(thisArg, () => true), TypeError)

);

        assertThrowsInstanceOf(() => arr[method](), TypeError);

        assertThrowsInstanceOf(() => arr[method](1), TypeError);

});

});

anyTypedArrayConstructors.filter(isFloatConstructor).forEach(constructor => {

    var arr = new constructor([-0, 0, 1, 5, NaN, 6]);

    assertEq(arr.findLast(v => Number.isNaN(v)), NaN);

    assertEq(arr.findLastIndex(v => Number.isNaN(v)), 4);

    assertEq(arr.findLast(v => Object.is(v, 0)), 0);

    assertEq(arr.findLastIndex(v => Object.is(v, 0)), 1);

    assertEq(arr.findLast(v => Object.is(v, -0)), -0);

    assertEq(arr.findLastIndex(v => Object.is(v, -0)), 0);

})

if (typeof reportCompare === "function")

    reportCompare(true, true);