A tiny async loader / dependency manager for modern browsers (961 bytes)
Installations
npm install loadjsDeveloper Guide
Typescript
No
Module System
CommonJS
Node Version
20.9.0
NPM Version
10.1.0
Score
96.1
Supply Chain
100
Quality
76.9
Maintenance
100
Vulnerability
100
License
Contributors
Unable to fetch Contributors
Languages
JavaScript (98.43%)
HTML (1.44%)
CSS (0.13%)
Developer
kubetail-org
Download Statistics
Total Downloads
66,414,098
Last Day
11,409
Last Week
154,810
Last Month
917,071
Last Year
11,421,355
GitHub Statistics
2,584 Stars
174 Commits
150 Forks
73 Watching
2 Branches
8 Contributors
Maintainers
Package Meta Information
Latest Version
4.3.0
Package Id
loadjs@4.3.0
Unpacked Size
932.65 kB
Size
206.91 kB
File Count
57
NPM Version
10.1.0
Node Version
20.9.0
Publised On
11 Apr 2024
Total Downloads
Cumulative downloads
Total Downloads
66,414,098
Last day
-75.9%
11,409
Compared to previous day
Last week
-31.4%
154,810
Compared to previous week
Last month
-9.1%
917,071
Compared to previous month
Last year
-3.3%
11,421,355
Compared to previous year
Daily Downloads
Weekly Downloads
Monthly Downloads
Yearly Downloads
Dev Dependencies
7
LoadJS
LoadJS is a tiny async loader for modern browsers (961 bytes).
Introduction
LoadJS is a tiny async loading library for modern browsers (IE9+). It has a simple yet powerful dependency management system that lets you fetch JavaScript, CSS and image files in parallel and execute code after the dependencies have been met. The recommended way to use LoadJS is to include the minified source code of loadjs.js in your <html> (possibly in the <head> tag) and then use the loadjs global to manage JavaScript dependencies after pageload.
LoadJS is based on the excellent $script library by Dustin Diaz. We kept the behavior of the library the same but we re-wrote the code from scratch to add support for success/error callbacks and to optimize the library for modern browsers. LoadJS is 961 bytes (minified + gzipped).
Here's an example of what you can do with LoadJS:
1<script src="//unpkg.com/loadjs@latest/dist/loadjs.min.js"></script> 2<script> 3 // define a dependency bundle and execute code when it loads 4 loadjs(['/path/to/foo.js', '/path/to/bar.js'], 'foobar'); 5 6 loadjs.ready('foobar', function() { 7 /* foo.js & bar.js loaded */ 8 }); 9</script>
You can also use more advanced syntax for more options:
1<script src="//unpkg.com/loadjs@latest/dist/loadjs.min.js"></script> 2<script> 3 // define a dependency bundle with advanced options 4 loadjs(['/path/to/foo.js', '/path/to/bar.js'], 'foobar', { 5 before: function(path, scriptEl) { /* execute code before fetch */ }, 6 async: true, // load files synchronously or asynchronously (default: true) 7 numRetries: 3 // see caveats about using numRetries with async:false (default: 0), 8 returnPromise: false // return Promise object (default: false) 9 }); 10 11 loadjs.ready('foobar', { 12 success: function() { /* foo.js & bar.js loaded */ }, 13 error: function(depsNotFound) { /* foobar bundle load failed */ }, 14 }); 15</script>
The latest version of LoadJS can be found in the dist/ directory in this repository:
- https://cdn.rawgit.com/kubetail-org/loadjs/4.3.0/dist/loadjs.js (for development)
- https://cdn.rawgit.com/kubetail-org/loadjs/4.3.0/dist/loadjs.min.js (for production)
It's also available from these public CDNs:
- UNPKG
- https://unpkg.com/loadjs@4.3.0/dist/loadjs.js (for development)
- https://unpkg.com/loadjs@4.3.0/dist/loadjs.min.js (for production)
- CDNJS
- https://cdnjs.cloudflare.com/ajax/libs/loadjs/4.3.0/loadjs.js (for development)
- https://cdnjs.cloudflare.com/ajax/libs/loadjs/4.3.0/loadjs.min.js (for production)
You can also use it as a CJS or AMD module:
1$ npm install --save loadjs
1var loadjs = require('loadjs'); 2 3loadjs(['/path/to/foo.js', '/path/to/bar.js'], 'foobar'); 4 5loadjs.ready('foobar', function() { 6 /* foo.js & bar.js loaded */ 7});
Browser Support
- IE9+ (
async: falsesupport only works in IE10+) - Opera 12+
- Safari 5+
- Chrome
- Firefox
- iOS 6+
- Android 4.4+
LoadJS also detects script load failures from AdBlock Plus and Ghostery in:
- Safari
- Chrome
Note: LoadJS treats empty CSS files as load failures in IE9-11 and uses rel="preload" to load CSS files in Edge (to get around lack of support for onerror events on <link rel="stylesheet"> tags)
Documentation
-
Load a single file
1loadjs('/path/to/foo.js', function() { 2 /* foo.js loaded */ 3}); -
Fetch files in parallel and load them asynchronously
1loadjs(['/path/to/foo.js', '/path/to/bar.js'], function() { 2 /* foo.js and bar.js loaded */ 3}); -
Fetch JavaScript, CSS and image files
1loadjs(['/path/to/foo.css', '/path/to/bar.png', 'path/to/thunk.js'], function() { 2 /* foo.css, bar.png and thunk.js loaded */ 3}); -
Force treat file as CSS stylesheet
1loadjs(['css!/path/to/cssfile.custom'], function() { 2 /* cssfile.custom loaded as stylesheet */ 3}); -
Force treat file as image
1loadjs(['img!/path/to/image.custom'], function() { 2 /* image.custom loaded */ 3}); -
Load JavaScript files as modules with non-module fallbacks (in browsers without module support)
1loadjs(['module!/path/to/foo.js', 'nomodule!/path/to/bar.js'], function() { 2 /* foo.js loaded with type="module" in browsers with module support, skipped silently in browsers without */ 3 /* bar.js loaded with type="text/javascript" in browsers without module support, skipped silently in browsers with */ 4}); -
Add a bundle id
1loadjs(['/path/to/foo.js', '/path/to/bar.js'], 'foobar', function() { 2 /* foo.js & bar.js loaded */ 3}); -
Use .ready() to define bundles and callbacks separately
1loadjs(['/path/to/foo.js', '/path/to/bar.js'], 'foobar'); 2 3loadjs.ready('foobar', function() { 4 /* foo.js & bar.js loaded */ 5}); -
Use multiple bundles in .ready() dependency lists
1loadjs('/path/to/foo.js', 'foo'); 2loadjs(['/path/to/bar1.js', '/path/to/bar2.js'], 'bar'); 3 4loadjs.ready(['foo', 'bar'], function() { 5 /* foo.js & bar1.js & bar2.js loaded */ 6}); -
Chain .ready() together
1loadjs('/path/to/foo.js', 'foo'); 2loadjs('/path/to/bar.js', 'bar'); 3 4loadjs 5 .ready('foo', function() { 6 /* foo.js loaded */ 7 }) 8 .ready('bar', function() { 9 /* bar.js loaded */ 10 }); -
Use Promises to register callbacks
1loadjs(['/path/to/foo.js', '/path/to/bar.js'], {returnPromise: true}) 2 .then(function() { /* foo.js & bar.js loaded */ }) 3 .catch(function(pathsNotFound) { /* at least one didn't load */ }); -
Check if bundle has already been defined
1if (!loadjs.isDefined('foobar')) { 2 loadjs(['/path/to/foo.js', '/path/to/bar.js'], 'foobar', function() { 3 /* foo.js & bar.js loaded */ 4 }); 5} -
Fetch files in parallel and load them in series
1loadjs(['/path/to/foo.js', '/path/to/bar.js'], { 2 success: function() { /* foo.js and bar.js loaded in series */ }, 3 async: false 4}); -
Add an error callback
1loadjs(['/path/to/foo.js', '/path/to/bar.js'], 'foobar', { 2 success: function() { /* foo.js & bar.js loaded */ }, 3 error: function(pathsNotFound) { /* at least one path didn't load */ } 4}); -
Retry files before calling the error callback
1loadjs(['/path/to/foo.js', '/path/to/bar.js'], 'foobar', { 2 success: function() { /* foo.js & bar.js loaded */ }, 3 error: function(pathsNotFound) { /* at least one path didn't load */ }, 4 numRetries: 3 5}); 6 7// NOTE: Using `numRetries` with `async: false` can cause files to load out-of-sync on retries -
Execute a callback before script tags are embedded
1loadjs(['/path/to/foo.js', '/path/to/bar.js'], { 2 success: function() {}, 3 error: function(pathsNotFound) {}, 4 before: function(path, scriptEl) { 5 /* called for each script node before being embedded */ 6 if (path === '/path/to/foo.js') scriptEl.crossOrigin = true; 7 } 8}); -
Bypass LoadJS default DOM insertion mechanism (DOM
<head>)1loadjs(['/path/to/foo.js'], { 2 success: function() {}, 3 error: function(pathsNotFound) {}, 4 before: function(path, scriptEl) { 5 document.body.appendChild(scriptEl); 6 7 /* return `false` to bypass default DOM insertion mechanism */ 8 return false; 9 } 10}); -
Use bundle ids in error callback
1loadjs('/path/to/foo.js', 'foo'); 2loadjs('/path/to/bar.js', 'bar'); 3loadjs(['/path/to/thunkor.js', '/path/to/thunky.js'], 'thunk'); 4 5// wait for multiple depdendencies 6loadjs.ready(['foo', 'bar', 'thunk'], { 7 success: function() { 8 // foo.js & bar.js & thunkor.js & thunky.js loaded 9 }, 10 error: function(depsNotFound) { 11 if (depsNotFound.indexOf('foo') > -1) {}; // foo failed 12 if (depsNotFound.indexOf('bar') > -1) {}; // bar failed 13 if (depsNotFound.indexOf('thunk') > -1) {}; // thunk failed 14 } 15}); -
Use .done() for more control
1loadjs.ready(['dependency1', 'dependency2'], function() { 2 /* run code after dependencies have been met */ 3}); 4 5function fn1() { 6 loadjs.done('dependency1'); 7} 8 9function fn2() { 10 loadjs.done('dependency2'); 11} -
Reset dependency trackers
1loadjs.reset(); -
Implement a require-like dependency manager
1var bundles = { 2 'bundleA': ['/file1.js', '/file2.js'], 3 'bundleB': ['/file3.js', '/file4.js'] 4}; 5 6function require(bundleIds, callbackFn) { 7 bundleIds.forEach(function(bundleId) { 8 if (!loadjs.isDefined(bundleId)) loadjs(bundles[bundleId], bundleId); 9 }); 10 loadjs.ready(bundleIds, callbackFn); 11} 12 13require(['bundleA'], function() { /* bundleA loaded */ }); 14require(['bundleB'], function() { /* bundleB loaded */ }); 15require(['bundleA', 'bundleB'], function() { /* bundleA and bundleB loaded */ });
Directory structure
loadjs/ ├── dist │  ├── loadjs.js │  ├── loadjs.min.js │  └── loadjs.umd.js ├── examples ├── gulpfile.js ├── LICENSE.txt ├── package.json ├── README.md ├── src │  └── loadjs.js ├── test └── umd-templates
Development Quickstart
-
Install dependencies
-
Clone repository
1$ git clone git@github.com:kubetail-org/loadjs.git 2$ cd loadjs -
Install node dependencies using npm
1$ npm install -
Build examples
1$ npm run build-examplesTo view the examples you can use any static file server. To use the
nodejshttp-server module:1$ npm install http-server 2$ npm run http-server -- -p 3000Then visit http://localhost:3000/examples
-
Build distribution files
1$ npm run build-distThe files will be located in the
distdirectory. -
Run tests
To run the browser tests first build the
loadjslibrary:1$ npm run build-testsThen visit http://localhost:3000/test
-
Build all files
1$ npm run build-all
No vulnerabilities found.
No security vulnerabilities found.