array-holes-slow.js

Enable keyboard shortcuts

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

var a = [0, , , 3];

a.slow = true;

Object.prototype[1] = 'peek1';

Array.prototype[2] = 'peek2';

var log = [];

for (var x of a)

    log.push(x);

assertEq(log[1], 'peek1');

assertEq(log[2], 'peek2');

assertEq(log.join(), "0,peek1,peek2,3");