Stage 4 (Finished)

What is it? The proposal is ready to be included in the standard.

What’s required? The following things are needed before a proposal can reach this stage:

  • Test 262 acceptance tests (roughly, unit tests for the language feature, written in JavaScript).
  • Two spec-compliant shipping implementations that pass the tests.
  • Significant practical experience with the implementations.
  • The ECMAScript spec editor must sign off on the spec text.

What’s next? The proposal will be included in the ECMAScript specification as soon as possible. When the spec goes through its yearly ratification as a standard, the proposal is ratified as part of it.

These stage details are taken from Dr. Axel Rauschmayer's blog post. You can read more about the TC39 process in their official process document.