diff options
Diffstat (limited to 'js/src/tests/test262/built-ins/Iterator/from/get-next-method-only-once.js')
-rw-r--r-- | js/src/tests/test262/built-ins/Iterator/from/get-next-method-only-once.js | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/Iterator/from/get-next-method-only-once.js b/js/src/tests/test262/built-ins/Iterator/from/get-next-method-only-once.js new file mode 100644 index 0000000000..efe706a72a --- /dev/null +++ b/js/src/tests/test262/built-ins/Iterator/from/get-next-method-only-once.js @@ -0,0 +1,49 @@ +// |reftest| shell-option(--enable-iterator-helpers) skip-if(!this.hasOwnProperty('Iterator')||!xulRuntime.shell) -- iterator-helpers is not enabled unconditionally, requires shell-options +// Copyright (C) 2023 Michael Ficarra. All rights reserved. +// This code is governed by the BSD license found in the LICENSE file. +/*--- +esid: sec-iterator.from +description: > + Gets the next method from the underlying iterator only once +info: | + Iterator.from ( O ) + + 2. Let iteratorRecord be ? GetIteratorFlattenable(O). + +features: [iterator-helpers] +flags: [] +---*/ +let nextGets = 0; +let nextCalls = 0; + +class CountingIterator { + get next() { + ++nextGets; + let iter = (function* () { + for (let i = 1; i < 5; ++i) { + yield i; + } + })(); + return function () { + ++nextCalls; + return iter.next(); + }; + } +} + +let iterator = new CountingIterator(); + +assert.sameValue(nextGets, 0, 'The value of `nextGets` is 0'); +assert.sameValue(nextCalls, 0, 'The value of `nextCalls` is 0'); + +iterator = Iterator.from(iterator); + +assert.sameValue(nextGets, 1, 'The value of `nextGets` is 1'); +assert.sameValue(nextCalls, 0, 'The value of `nextCalls` is 0'); + +iterator.toArray(); + +assert.sameValue(nextGets, 1, 'The value of `nextGets` is 1'); +assert.sameValue(nextCalls, 5, 'The value of `nextCalls` is 5'); + +reportCompare(0, 0); |