Google Apps Script 支持哪个版本的 ECMA-262？

Question

According to this thread from the old Google Group, Apps Script is based on ECMA-262 3rd Edition.

This would seem to be supported by the fact that auto-completion in the editor displays 3rd Edition array functions.

However the following code runs perfectly well, which casts doubt on the matter:

var array = [
  1,2,3,4,5
];

Logger.log("forEach:");
array.forEach(function (item,idx,arr) {
  Logger.log(item); 
});

Note the use of ECMA-262 5th Edition Array function forEach.

Would someone authoritative mind giving a definitive answer on why this is the case? And whether it's safe to rely on all 5th Edition features or a sub-set that have been implemented and seem to work?

Answer 1

The documentation says that the old runtime is based on Mozilla's Rhino JavaScript interpreter which provides a subset of ECMAScript 5 and is based on 1.6, with a smattering of 1.7 and 1.8.

The new Apps Script runtime is supported by the V8 runtime with few exceptions like E6 Modules.

Answer 2

From Built-in Google Services

Apps Script supports two JavaScript runtimes: the modern V8 runtime and an older one powered byMozilla's Rhino JavaScript interpreter .

The V8 runtime supports modern ECMAScript syntax and features. The Rhino runtime is based on the older JavaScript 1.6 standard, plus a few features from 1.7 and 1.8 . You can freely choose which runtime to use with your script, but the V8 runtime is strongly recommended.