ECMAScript and JavaScript
JavaScript is an implementation of the language standard ECMAScript. The Ecma TC39 (Ecma Technical Committee 39) committee is responsible for evolving the ECMAScript programming language and authoring the specification. It is also responsible for the official ECMAScript Conformance Test Suite, that can be used to check how closely a JavaScript implementation follows the ECMAScript specification.
Skin Disease!
JavaScript’s original creator, Brenan Eich, has commented that “ECMAScript was always an unwanted trade name that sounds like a skin disease.”
Versions
The latest version is ECMAScript 8 - published June 2017. From the 6th Edition, the official name became ‘ECMAScript
Conformance
The Test262 ECMAScript Test Suite is used to attempt to measure conformity to the latest specification. As of April 2018 Wikipedia shows this as:
| Scripting engine | Reference application(s) | Conformance ES5 | Conformance ES6 | Conformance Newer (2016+) |
|---|---|---|---|---|
| SpiderMonkey | Firefox | 100% | 97% | 77% |
| Chrome V8 | Google Chrome, Opera | 100% | 97% | 93% |
| JavaScriptCore (Nitro) | Safari | 97% | 99% | 64% |
| Chakra | Microsoft Edge | 100% | 96% | 60% |
TC39 5 Stage Process
New proposals follow the The TC39 5 stage process
| Stage | Name | Description |
|---|---|---|
| 0 | Strawman | New proposals |
| 1 | Proposal | Making the case for the addition |
| 2 | Draft | Formalising the syntax and semantics of the proposal - still experimental and subject to change |
| 3 | Candidate | Proposal now spec compliant, and only critical changes allowed |
| 4 | Finished | Ready for inclusion in the next ECMAScript release |
All new changes are tracked in the proposals repository