Dan503 / load-js

A small function for loading a js file before running code, will only ever load the file once per page load.

load-js

A small function for loading a js file before running code.

This function is ideal for loading up something like a polyfill before running code that is dependant on that polyfill.

Install

Install using npm which comes bundled with Node.js.

npm i @dan503/load-js

Usage

// Import using one of these 2 methods
import loadJS from '@dan503/load-js' // ES Module import syntax
var loadJS = require('@dan503/load-js').default // Common JS import syntax

// Use the first parameter to point to where the external js file needs to be downloaded from.
loadJS('https://www.website.com/js-file.js', () => {
	// The 2nd parameter is a callback function.
	// The callback will be called once the JS file has finished downloading.
})

Key features

Call multiple times, only download the file once

It will only ever download the target file once per page load even if called multiple times.

Trigger callback immediately if the file is already downloaded

If the script has already been downloaded, it will trigger the callback function immediately in a synchronous fashion.

Callbacks retain source order

It will call all of the callbacks in the order that they were declared in when the script has finished loading.

Super simple syntax

As you can see from the usage example above, the usage syntax is extremely simple and easy to remember.

Quality assured with Cypress tests

This project uses Cypress end to end tests to ensure the function does what it is supposed to.

Supports TypeScript

This function has been written in TypeScript so it has full TypeScript support built in.