A small modification to JavaScript syntax allows trailing comma in formal parameter lists and in argument lists. For example, all the following become valid: function f(a, b,) { return a + b } let g = (a, b,) => a + b f(1, 2,) + g(3, 4,) This is expected to be available by default in Chrome 58.


Editor's draft

Status in Chromium


Enabled by default (tracking bug) in:

  • Chrome for desktop release 58
  • Chrome for Android release 58
  • Android WebView release 58

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

  • In development
  • Shipped/Shipping
  • In development
  • No signals


Last updated on 2020-11-09