Source code
Revision control
Copy as Markdown
Other Tools
// |reftest| async
// This file was procedurally generated from the following sources:
// - src/function-forms/unscopables-with.case
// - src/function-forms/default/async-arrow-function.template
/*---
description: Symbol.unscopables behavior across scope boundaries (async arrow function expression)
esid: sec-async-arrow-function-definitions
features: [globalThis, Symbol.unscopables, async-functions]
flags: [generated, noStrict, async]
info: |
14.7 Async Arrow Function Definitions
AsyncArrowFunction :
...
CoverCallExpressionAndAsyncArrowHead => AsyncConciseBody
AsyncConciseBody :
{ AsyncFunctionBody }
...
Supplemental Syntax
When processing an instance of the production AsyncArrowFunction :
CoverCallExpressionAndAsyncArrowHead => AsyncConciseBody the interpretation of
CoverCallExpressionAndAsyncArrowHead is refined using the following grammar:
AsyncArrowHead :
async ArrowFormalParameters
...
Let envRec be lex's EnvironmentRecord.
Let exists be ? envRec.HasBinding(name).
HasBinding
...
If the withEnvironment flag of envRec is false, return true.
Let unscopables be ? Get(bindings, @@unscopables).
If Type(unscopables) is Object, then
Let blocked be ToBoolean(? Get(unscopables, N)).
If blocked is true, return false.
(The `with` Statement) Runtime Semantics: Evaluation
...
Set the withEnvironment flag of newEnv’s EnvironmentRecord to true.
...
---*/
let count = 0;
var v = 1;
globalThis[Symbol.unscopables] = {
v: true,
};
{
count++;
var callCount = 0;
// Stores a reference `ref` for case evaluation
var ref = async (x) => {
count++;
with (globalThis) {
count++;
assert.sameValue(v, undefined, 'The value of `v` is expected to equal `undefined`');
}
count++;
var v = x;
with (globalThis) {
count++;
assert.sameValue(v, 10, 'The value of `v` is 10');
v = 20;
}
assert.sameValue(v, 20, 'The value of `v` is 20');
assert.sameValue(globalThis.v, 1, 'The value of globalThis.v is 1');
callCount = callCount + 1;
};
ref(10).then(() => {
assert.sameValue(callCount, 1, 'async arrow function invoked exactly once')
}).then($DONE, $DONE);
count++;
}
assert.sameValue(count, 6, 'The value of `count` is 6');