array-holes-4.js - mozsearch

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// for-of on an Array consults the prototype chain when it encounters a hole.

load(libdir + "iteration.js");

var m = {1: 'peek'};

var a = [0, , 2, 3];

a.__proto__ = m;

var log = [];

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

for (var x of a)

    log.push(x);

assertEq(log[1], 'peek');

assertEq(log.join(), "0,peek,2,3");