diff --git a/doc/guides/writing-tests.md b/doc/guides/writing-tests.md index 21ae1022a3c769..f565f3847b2bb1 100644 --- a/doc/guides/writing-tests.md +++ b/doc/guides/writing-tests.md @@ -189,6 +189,21 @@ const assert = require('assert'); const freelist = require('internal/freelist'); ``` +### ES.Next features + +For performance considerations, we only use a selected subset of ES.Next +features in JavaScript code in the `lib` directory. However, when writing +tests, for the ease of backporting, it is encouraged to use those ES.Next +features that can be used directly without a flag in [all maintained branches] +(https://github.com/nodejs/lts), you can check [node.green](http://node.green) +for all available features in each release. + +For example: + +* `let` and `const` over `var` +* Template literals over string concatenation +* Arrow functions when appropriate + ## Naming Test Files Test files are named using kebab casing. The first component of the name is