src/arguments/args-trailing-comma-spread-operator.case

// Copyright (C) 2018 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.

/*---
desc: A trailing comma should not increase the arguments.length, using spread args
template: default
info: |
    Trailing comma in the arguments list

    Left-Hand-Side Expressions

    Arguments :
        ( )
        ( ArgumentList )
        ( ArgumentList , )

    ArgumentList :
        AssignmentExpression
        ... AssignmentExpression
        ArgumentList , AssignmentExpression
        ArgumentList , ... AssignmentExpression
---*/

//- setup
var arr = [2, 3];

//- args
42, ...[1], ...arr,
//- body
assert.sameValue(arguments.length, 4);
assert.sameValue(arguments[0], 42);
assert.sameValue(arguments[1], 1);
assert.sameValue(arguments[2], 2);
assert.sameValue(arguments[3], 3);