babel-blacklist's Introduction

babel-blacklist

Generates a blacklist for features available by default in Node/io.js based on version.

Install with npm install --save-dev babel-blacklist and use it like so (e.g. in a require hook):

require("babel/register")({
  blacklist: require("babel-blacklist")()
})

This makes Babel only transpile what it needs to in your engine.

Documentation

blacklist(version?: string, isStaging?)
blacklist(version: [major, minor, patch], isStaging?)

version

If it's a string, it should be of either the form "vN.N.N" (like "v0.12.0") or "N.N.N" (like "0.12.0"). It is permissible to omit the patch or even the minor, in which it defaults to 0. The 'major' field is required. Note that it doesn't accept shorthands like "v0.12.x" or other npm semver abbreviations. This does not use that syntax.

If it's an array, it is treated as a 3-tuple [major, minor, patch], where each of them are treated as numbers, coerced if they are not. The major field is required. The rest default to 0.

This defaults to process.version.
isStaging

If truthy, use the table for io.js' --es-staging flag. Defaults to true if version is not given and --es-staging is set, false otherwise.

Calls to this are memoized.

blacklist.list

Get a list of all the flags for each version. This an object with three keys:

defaults - The features not needed by default.
staging - The features not needed with --es-staging
compareVersion(a, b) - Compare two versions a and b. Returns 1 if greater, 0 if same, and -1 if less.

Both defaults and staging are arrays of objects containing the following properties:

version - An object of the form {major, minor, patch}, representing the relative version.
blacklist - A list of strings safe for the Babel blacklist option.

Note that this property, defaults, and staging are lazy-loaded for memory reasons.