object-spread.js - mozsearch

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function test() {

    var from, to;

    // From values.

    from = {x: 1, y: 2};

    to = {...from};

    assertEq(to.y, 2);

    to = {...from, ...from};

    assertEq(to.y, 2);

    // From getter.

    var c = 7;

    from = {x: 1, get y() { return ++c; }};

    to = {...from};

    assertEq(to.y, 8);

    to = {...from, ...from};

    assertEq(to.y, 10);

    // Array with dense elements.

    from = [1, 2, 3];

    to = {...from};

    assertEq(to[2], 3);

    assertEq("length" in to, false);

    // Object with sparse elements and symbols.

    from = {x: 1, 1234567: 2, 1234560: 3, [Symbol.iterator]: 5, z: 3};

    to = {...from};

    assertEq(to[1234567], 2);

    assertEq(Object.keys(to).toString(), "1234560,1234567,x,z");

    assertEq(to[Symbol.iterator], 5);

    // Typed array.

    from = new Int32Array([1, 2, 3]);

    to = {...from};

    assertEq(to[1], 2);

    // Primitive string.

    from = "foo";

    to = {...from};

    assertEq(to[0], "f");

    // String object.

    from = new String("bar");

    to = {...from};

    assertEq(to[2], "r");

test();

test();

test();