@balena/es-version
This module allows specifying a target es version for other modules to require, currently supported target versions:
- es3 (default)
- es5
- es2015
- es2016
- es2017
- es2018
- es2019
- es2020
- es2021
- es2022
- esnext
Usage as a client
- Add @balena/es-version to your package.json with a
^version specifier, eg
"@balena/es-version": "^1.0.0",
Note: If using locked dependences, eg package-lock.json/npm-shrinkwrap.json/etc, then make sure to also dedupe the module so that the same instance of the module is used everywhere.
- Within your module require it before anything else and set the desired version:
// Must be set before the first require of an @balena/es-version supporting module
require('@balena/es-version').set('es5');
and then the closest matching version will be used by any module that supports choosing the target version, with the priority being:
- exact match
- closest match under the desired version
- lowest supported version
Usage as a module provider
- Add @balena/es-version to your package.json with a
^version specifier, eg
"@balena/es-version": "^1.0.0",
- Generate builds for the es versions you wish to support along with types for the shim you'll create, eg
"build-es5": "tsc --target es5 --outDir es5",
"build-es2015": "tsc --target es2015 --outDir es2015",
"build-es2018": "tsc --target es2018 --outDir es2018",
"build-types": "tsc --emitDeclarationOnly --outDir .",
"build": "npm run build-es5 && npm run build-es2015 && npm run build-es2018 && npm run build-types",
- Create a shim to use as your entry-point which loads the desired version, eg
// First get the es version to use:
var esVersion = require('@balena/es-version').get(['es5', 'es2015', 'es2018');
// Then include/return the correct version of your module, eg
module.exports = module.exports = require('./' + esVersion);
Note: This must be compatible with your lowest supported es version
- Point your package.json to the new shim and types, eg
"main": "index.js",
"types": "index.d.ts",
- It is also recommended to add a "browser" entry to a fixed es version in your package.json in order to support browser bundlers with default config, eg
"browser": "es5"