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// Copyright 2019 Google, LLC. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: prod-OptionalExpression
description: >
optional chain in init/test/update of for statement
info: |
IterationStatement
for (Expression; Expression; Expression) Statement
features: [optional-chaining]
---*/
// OptionalExpression in test.
let count;
const obj = {a: true};
for (count = 0; obj?.a; count++) {
if (count > 0) break;
}
assert.sameValue(count, 1);
// OptionalExpression in init/test/update.
let count2 = 0;
const obj2 = undefined;
for (obj?.a; obj2?.a; obj?.a) { count2++; }
assert.sameValue(count2, 0);
for (obj?.a; undefined?.a; obj?.a) { count2++; }
assert.sameValue(count2, 0);
// Short-circuiting
let touched = 0;
const obj3 = {
get a() {
count++;
return undefined; // explicit for clarity
}
};
for (count = 0; true; obj3?.a?.[touched++]) {
if (count > 0) { break; }
}
assert.sameValue(count, 1);
assert.sameValue(touched, 0);
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