JSTests/test262/test/language/expressions/arrow-function/dstr/ary-ptrn-rest-id-elision.js

// This file was procedurally generated from the following sources:
// - src/dstr-binding/ary-ptrn-rest-id-elision.case
// - src/dstr-binding/default/arrow-function.template
/*---
description: Rest element following elision elements (arrow function expression)
esid: sec-arrow-function-definitions-runtime-semantics-evaluation
features: [destructuring-binding]
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
    ArrayBindingPattern : [ Elisionopt BindingRestElement ]
    1. If Elision is present, then
       a. Let status be the result of performing
          IteratorDestructuringAssignmentEvaluation of Elision with
          iteratorRecord as the argument.
       b. ReturnIfAbrupt(status).
    2. Return the result of performing IteratorBindingInitialization for
       BindingRestElement with iteratorRecord and environment as arguments.
---*/
var values = [1, 2, 3, 4, 5];

var callCount = 0;
var f;
f = ([ , , ...x]) => {
  assert(Array.isArray(x));
  assert.sameValue(x.length, 3);
  assert.sameValue(x[0], 3);
  assert.sameValue(x[1], 4);
  assert.sameValue(x[2], 5);
  assert.notSameValue(x, values);
  callCount = callCount + 1;
};

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