semantics-10.js - mozsearch

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// The LHS of a for-loop is not bound to a particular scope until after the .next() method returns.

var obj = {};

// Test 1

function* g() {

    obj.x = 0;

    yield 1;

var x = 2, n = 0;

with (obj) {

    for (x of g())  // g().next() inserts a binding for x on obj

        n++;

assertEq(x, 2);

assertEq(obj.x, 1);

assertEq(n, 1);

// Test 2

function* h() {

    delete obj.x;

    yield 3;

n = 0;

with (obj) {

    for (x of h())  // h().next() deletes the binding for x on obj

        n++;

assertEq(x, 3);

assertEq("x" in obj, false);

assertEq(n, 1);