JSTests/stress/regexp-last-index-writable.js

function shouldBe(actual, expected) {
    if (actual !== expected)
        throw new Error('bad value: ' + actual);
}

function shouldThrow(func, message) {
    var error = null;
    try {
        func();
    } catch (e) {
        error = e;
    }
    if (!error)
        throw new Error("not thrown.");
    if (String(error) !== message)
        throw new Error("bad error: " + String(error));
}

(function regExpLastIndex() {
    var regexp = new RegExp('Cocoa');
    regexp.lastIndex = 'Hello';
    shouldBe(Reflect.get(regexp, 'lastIndex'), 'Hello');
    regexp.lastIndex = 42;
    shouldBe(Reflect.get(regexp, 'lastIndex'), 42);

    regexp.lastIndex = "Hello";
    shouldBe(Reflect.get(regexp, 'lastIndex'), 'Hello');

    shouldBe(Reflect.defineProperty(regexp, 'lastIndex', {
        value: 42,
        writable: false
    }), true);
    shouldBe(Reflect.get(regexp, 'lastIndex'), 42);
    shouldThrow(function () {
        'use strict';
        regexp.lastIndex = 'NG';
    }, `TypeError: Attempted to assign to readonly property.`);
    shouldBe(Reflect.get(regexp, 'lastIndex'), 42);

    shouldThrow(function () {
        'use strict';
        regexp.lastIndex = "NG";
    }, `TypeError: Attempted to assign to readonly property.`);

    shouldThrow(function () {
        'use strict';
        Object.defineProperty(regexp, 'lastIndex', {
            value: 'NG'
        });
    }, `TypeError: Attempting to change value of a readonly property.`);
    shouldBe(Reflect.get(regexp, 'lastIndex'), 42);
}());