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// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
namespace object {
transitioning macro ObjectFromEntriesFastCase(implicit context: Context)(
iterable: JSAny): JSObject labels IfSlow {
typeswitch (iterable) {
case (array: FastJSArrayWithNoCustomIteration): {
const elements: FixedArray =
Cast<FixedArray>(array.elements) otherwise IfSlow;
const length: Smi = array.length;
const result: JSObject = NewJSObject();
for (let k: Smi = 0; k < length; ++k) {
const value: JSAny = array::LoadElementOrUndefined(elements, k);
const pair: KeyValuePair =
collections::LoadKeyValuePairNoSideEffects(value)
otherwise IfSlow;
// Bail out if ToPropertyKey will attempt to load and call
// Symbol.toPrimitive, toString, and valueOf, which could
// invalidate assumptions about the iterable.
if (Is<JSReceiver>(pair.key)) goto IfSlow;
FastCreateDataProperty(result, pair.key, pair.value);
}
return result;
}
case (JSAny): {
goto IfSlow;
}
}
}
transitioning javascript builtin
ObjectFromEntries(
js-implicit context: NativeContext, receiver: JSAny)(...arguments): JSAny {
const iterable: JSAny = arguments[0];
try {
if (IsNullOrUndefined(iterable)) goto Throw;
return ObjectFromEntriesFastCase(iterable) otherwise IfSlow;
} label IfSlow {
const result: JSObject = NewJSObject();
const fastIteratorResultMap: Map = GetIteratorResultMap();
let i: iterator::IteratorRecord = iterator::GetIterator(iterable);
try {
assert(!IsNullOrUndefined(i.object));
while (true) {
const step: JSReceiver =
iterator::IteratorStep(i, fastIteratorResultMap)
otherwise return result;
const iteratorValue: JSAny =
iterator::IteratorValue(step, fastIteratorResultMap);
const pair: KeyValuePair = collections::LoadKeyValuePair(iteratorValue);
FastCreateDataProperty(result, pair.key, pair.value);
}
return result;
} catch (e) deferred {
iterator::IteratorCloseOnException(i);
ReThrow(context, e);
}
} label Throw deferred {
ThrowTypeError(MessageTemplate::kNotIterable);
}
}
} // namespace object
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