JSTests/test262/test/language/expressions/arrow-function/dstr/dflt-ary-ptrn-elem-ary-elision-init.js

// This file was procedurally generated from the following sources:
// - src/dstr-binding/ary-ptrn-elem-ary-elision-init.case
// - src/dstr-binding/default/arrow-function-dflt.template
/*---
description: BindingElement with array binding pattern and initializer is used (arrow function expression (default parameter))
esid: sec-arrow-function-definitions-runtime-semantics-evaluation
features: [generators, destructuring-binding, default-parameters]
flags: [generated]
info: |
    ArrowFunction : ArrowParameters => ConciseBody

    [...]
    4. Let closure be FunctionCreate(Arrow, parameters, ConciseBody, scope, strict).
    [...]

    9.2.1 [[Call]] ( thisArgument, argumentsList)

    [...]
    7. Let result be OrdinaryCallEvaluateBody(F, argumentsList).
    [...]

    9.2.1.3 OrdinaryCallEvaluateBody ( F, argumentsList )

    1. Let status be FunctionDeclarationInstantiation(F, argumentsList).
    [...]

    9.2.12 FunctionDeclarationInstantiation(func, argumentsList)

    [...]
    23. Let iteratorRecord be Record {[[iterator]]:
        CreateListIterator(argumentsList), [[done]]: false}.
    24. If hasDuplicates is true, then
        [...]
    25. Else,
        b. Let formalStatus be IteratorBindingInitialization for formals with
           iteratorRecord and env as arguments.
    [...]

    13.3.3.6 Runtime Semantics: IteratorBindingInitialization

    BindingElement : BindingPatternInitializer opt

    [...]
    2. If iteratorRecord.[[done]] is true, let v be undefined.
    3. If Initializer is present and v is undefined, then
       a. Let defaultValue be the result of evaluating Initializer.
       b. Let v be ? GetValue(defaultValue).
    4. Return the result of performing BindingInitialization of BindingPattern
       with v and environment as the arguments.

---*/
var first = 0;
var second = 0;
function* g() {
  first += 1;
  yield;
  second += 1;
};

var callCount = 0;
var f;
f = ([[,] = g()] = []) => {
  assert.sameValue(first, 1);
  assert.sameValue(second, 0);
  callCount = callCount + 1;
};

f();
assert.sameValue(callCount, 1, 'arrow function invoked exactly once');