@vrbo/nimbuild-corejs


Performant generation of coreJS polyfill bundles optimized for target browsers at runtime

Why

Read: https://github.com/zloirock/core-js/blob/master/docs/2019-03-19-core-js-3-babel-and-a-look-into-the-future.md#better-optimization-of-polyfill-loading

> A service like this one integrated with a good polyfills source like core-js, which only loads the needed polyfills by statically analyzing the source like Babel's useBuiltIns: usage option does could cause a revolution in the way we think about polyfills.

This module is the core of what is needed to fulfill the next generation approach to loading polyfills.

Installation

``bash
npm install --save @vrbo/nimbuild-corejs
`

Usage

Import module, configure, and prime cache

`javascript
const {
addSupported,
clearSupported,
initializeSupported,
primeCache,
serializeCache,
deserializeCache
} = require('@vrbo/nimbuild-corejs');

// Initialize supported corejs modules
initializeSupported(); // use nimbuild-corejs defaults
// or customize supported corejs modules
initializeSupported({
'my-default': {
include: [
/ custom core-js modules /
],
exclude: [
/ custom core-js modules /
]
}
});

// Runs webpacknimbuild.run() on every browser platform
await primeCache();

// Get serialized cache
const serializedData = serializeCache();

// Set cache from serialized data
deserializeCache(serializedData);
`

When processing an HTTP request, generate coreJS polyfill string with this usage:

`javascript
const {getPolyfillString} = require('@vrbo/nimbuild-corejs');
const coreJSData = await getPolyfillString({
include: ['es.*'],
exclude: [],
logger: {log: console.log},
minify: true,
uaString: http.headers['user-agent']
});
return coreJSData.script; // polyfill string
`

Development

$3

`bash
npm start
`

$3

This projects supports auto-formatting of source code! Simply find your favorite IDE from the list in the following list: https://prettier.io/docs/en/editors.html

For VSCode support, perform the following steps:

- Launch VS Code Quick Open (Ctrl+P)
- Paste the following command, and press enter:

`
ext install esbenp.prettier-vscode
``