JSTests/stress/typedarray-construct-iterator.js

// Test a bunch of things about typed array constructors with iterators.

// Test that the dfg actually respects iterators.
let foo = [1,2,3,4];

function iterator() {
    return { i: 0,
             next: function() {
                 if (this.i < foo.length/2) {
                     return { done: false,
                              value: foo[this.i++]
                            };
                 }
                 return { done: true };
             }
           };
}

foo[Symbol.iterator] = iterator;

(function body() {

    for (var i = 1; i < 100000; i++) {
        if (new Int32Array(foo).length !== 2)
            throw "iterator did not run";
    }

})();

// Test that the optimizations used for iterators during construction is valid.

foo = { 0:0, 1:1, 2:2, 3:3 };
count = 4;
foo.__defineGetter__("length", function() {
    return count--;
});

foo[Symbol.iterator] = Array.prototype[Symbol.iterator];

if (new Int32Array(foo).length !== 2)
    throw "iterator did not run";

// Test that we handle length is unset... whoops.

foo = { 0:0, 2:2, 3:3 };

if (new Int32Array(foo).length !== 0)
    throw "did not handle object with unset length";

// Test that we handle prototypes with accessors.

foo = { 0:0, 2:2, 3:3 };
foo[Symbol.iterator] = Array.prototype[Symbol.iterator];
foo.length = 4;
bar = { };

bar.__defineGetter__("1", function() {
    foo.length = 0;
    return 1;
});


foo.__proto__ = bar;

if (new Int32Array(foo).length !== 2)
    throw "did not handle object with accessor on prototype";