JSTests/stress/for-in-tests.js

function shouldThrowSyntaxError(script) {
    let error;
    try {
        eval(script);
    } catch (e) {
        error = e;
    }

    if (!(error instanceof SyntaxError))
        throw new Error('Expected SyntaxError!');
}

(function() {
    // Iterate over an array with normal indexed properties.
    var foo = function() {
        var a = [1, 2, 3, 4, 5];
        var sum = 0;
        var result = "";
        for (var p in a)
            result += a[p];
        return result;
    };
    noInline(foo);
    for (var i = 0; i < 10000; ++i) {
        if (foo() !== "12345")
            throw new Error("bad result");
    }
    foo(null);
})();
(function() {
    // Iterate over an object with normal non-indexed properties.
    var foo = function() {
        var o = {};
        o.x = 1;
        o.y = 2;
        o.z = 3;
        var result = "";
        for (var p in o)
            result += o[p];
        return result;
    };
    noInline(foo);
    for (var i = 0; i < 10000; ++i) {
        if (foo() !== "123")
            throw new Error("bad result");
    }
    foo(null);
})();
(function() {
    // Iterate over an object with both indexed and non-indexed properties.
    var foo = function() {
        var o = {};
        o.x = 1;
        o.y = 2;
        o.z = 3;
        o[0] = 4;
        o[1] = 5;
        o[2] = 6;
        var result = "";
        for (var p in o)
            result += o[p];
        return result;
    };
    noInline(foo);
    for (var i = 0; i < 10000; ++i) {
        if (foo() != "456123")
            throw new Error("bad result");
    }
    foo(null);
})();
(function() {
    // Iterate over an array with both indexed and non-indexed properties.
    var foo = function() {
        var a = [4, 5, 6];
        a.x = 1;
        a.y = 2;
        a.z = 3;
        var result = "";
        for (var p in a)
            result += a[p];
        return result;
    };
    noInline(foo);
    for (var i = 0; i < 10000; ++i) {
        if (foo() !== "456123")
            throw new Error("bad result");
    }
    foo(null);
})();
(function() {
    var foo = function(a, b) {
        for (var p in b) {
            var f1 = a[p];
            var f2 = b[p];
            if (f1 === f2)
                continue;
            a[p] = b[p];
        }
    };
    noInline(foo);
    for (var i = 0; i < 10000; ++i) {
        var o1 = {};
        var o2 = {};
        o2.x = 42;
        o2.y = 53;
        foo(o1, o2);
        if (o1.x !== o2.x)
            throw new Error("bad result: " + o1.x + "!==" + o2.x);
        if (o1.y !== o2.y)
            throw new Error("bad result: " + o1.y + "!==" + o2.y);
    }
})();

(function() {
    var foo = function(a, b) {
        for (var p = b in a) {}
        return p;
    };
    noInline(foo);
    for (var i = 0; i < 10000; ++i) {
        var expected = 'expected-result';
        var result = foo({}, expected);
        if (expected !== result)
            throw new Error("bad result: " + result + "!==" + expected);
    }
    for (var i = 0; i < 10000; ++i) {
        var expected = 'a';
        var result = foo({a:'abcd'}, expected);
        if (expected !== result)
            throw new Error("bad result: " + result + "!==" + expected);
    }
    for (var i = 0; i < 10000; ++i) {
        var expected = 'b';
        var result = foo({a:'abcd', b: 'bcde'}, expected);
        if (expected !== result)
            throw new Error("bad result: " + result + "!==" + expected);
    }

    for (var i = 0; i < 10000; ++i) {
        var expected = 'c';
        var o = {a:'abcd', b: 'bcde'};
        o.c = 'cdef';
        var result = foo(o, expected);
        if (expected !== result)
            throw new Error("bad result: " + result + "!==" + expected);
    }
})();

(function() {
    var boo = function () { return 'expected-result'; };
    var foo = function(a) {
        for (var p = boo() in a) {}
        return p;
    };
    noInline(foo);
    for (var i = 0; i < 10000; ++i) {
        var expected = 'expected-result';
        var result = foo({});
        if (expected !== result)
            throw new Error("bad result: " + result + "!==" + expected);
    }
})();

shouldThrowSyntaxError(
    `function foo(a, b) {
        {
            let p = 'some-value';
            for (var p = b in a) {}
        }
    }`
);

(function() {
    var foo = function(a, b, c) {
        for (var p = b + c in a) {}
        return p;
    };
    noInline(foo);
    for (var i = 0; i < 10000; ++i) {
        var expected = 'expected-result';
        var result = foo({}, 'expected', '-result');
        if (expected !== result)
            throw new Error("bad result: " + result + "!==" + expected);
    }
})();

shouldThrowSyntaxError(
    `function foo() {
        'use strict';
        for (var i = 0 in {}) {}
    }`
);

shouldThrowSyntaxError(
    `function foo() {
        const i = 10;
        for (var i = 0 in {}) {}
    }`
);