Robert Rossmann Robert Rossmann - 7 months ago 25
Node.js Question

ECMAScript 6 features available in Node.js 0.12

A new stable release of Node.js (0.12) has landed recently with an upgraded Google's v8 JavaScript engine, v3.28.73.

What ECMAScript 6 features are currently present in Node.js, without using the

I have checked several sites claiming to list the ES 6 features but all of them seem out of date - most prominently, this table (Update: now updated with current Node.js status as of 0.12), because several of the features are listed as requiring the
flag while I found some of them being enabled by default (Maps, Sets, Symbols, to name a few). Update: Node specific tables have since been made available

Also, trying to google this information purely for the v8 engine gives too up-to-date information - current v8 release is 4.2.*, which is quite ahead of what Node.js uses.

My hopes are that this question (and its answers) will become a comprehensive summary on what ES 6 features are now available to Node.js developers.

ES 6 features enabled in Node.js 0.12 I currently know of:

  • Maps, Sets / WeakMaps, WeakSets

  • Symbols

  • Object.observe

  • Promises

  • Number

    • .isInteger

    • .isSafeInteger

    • .isNaN

    • .EPSILON



  • Math

    • .clz32

    • .imul

    • .sign

    • .log10

    • .log2

    • .log1p

    • .expm1

    • .cosh

    • .sinh

    • .tanh

    • .acosh

    • .asinh

    • .atanh

    • .trunc

    • .fround

    • .cbrt

    • .hypot


Features without --harmony flag:

I thinks that's all that we have without --harmony flag.

Features with --harmony flag:

I think that's all. Maybe if I forgot something - I'll add it later to the list.