A microfrontend module loader
Installation
Migration from RequireJs
Register a package
Require a package
Override amd dependencies
Require.when - ONLY load after explicit define/register
Define a package
RequireEs options
RequireEs events
WebPack / Rollup bundling for RequireEs
Custom elements support
Require-es will:
The project will be structured in 3 parts:
Add the package to your project
npm install requirees --save
Serve the file in node_modules/requirees/build/requirees.js in the header of your webpage (9Kb Gzipped)
<!DOCTYPE html>
<html>
<head>
<title>Pagetitle</title>
<script src="scripts/requirees.js"></script>
</head>
<body></body>
</html>
RequireEs allows a soft transition from RequireJs. This means that most syntax of RequireJs, is also supported in RequireEs:
In a later version, require.config({shim}) will be supported as well.
More info on RequireJs: https://requirejs.org/
require.register({
packageName1(@)(version)(.filetype)(-default): [
url(.filetype),
url(.filetype),
url(.filetype),
...
],
packageName2(@)(version)(.filetype)(-default): {
versions,
url,
urls
}
});
| Key | Description |
|---|---|
| PackageName | the name of the package |
| Version | the version-number in string format: major.minor(.patch)(.build)(-releaseCandidate) |
| Filetype | the file-extension - js/css/txt/xml/json/html/wasm/tag |
| Default | indicates the default version |
| Versions | array of versions to fill out in the URL (use placeholder ${version} in the url-string) |
| Url | single url string |
| Urls | multiple urls for 1 package |
Note - Determining the version number, happens in this order:
- Is a 'versions' attribute present in the package-value
- Is '@version' present in the package-name
- Is a version present in the url (cdnjs.com/17.0.2/package.js)
//register react, version '17.0.2'
require.register({
react: 'https://cdnjs.cloudflare.com/ajax/libs/react/17.0.2/umd/react.production.min.js'
});
//register react, versions '0.14.9', '15.6.2', '15.7.0', '16.14.0' (set as default), '17.0.2'
require.register({
react: {
versions: ['0.14.9', '15.6.2', '15.7.0'],
url: 'https://cdnjs.cloudflare.com/ajax/libs/react/${version}/react.min.js'
},
'react@16.14.0-default': 'https://cdnjs.cloudflare.com/ajax/libs/react/16.14.0/umd/react.production.min.js',
'react@17.0.2': 'https://cdnjs.cloudflare.com/ajax/libs/react/17.0.2/umd/react.production.min.js'
});
//register react, versions '15.7.0', '16.14.0', '17.0.2'
require.register({
react: [
'https://cdnjs.cloudflare.com/ajax/libs/react/15.7.0/react.min.js',
'https://cdnjs.cloudflare.com/ajax/libs/react/16.14.0/umd/react.production.min.js',
'https://cdnjs.cloudflare.com/ajax/libs/react/17.0.2/umd/react.production.min.js',
]
});
//register bootstrap, both css and js
require.register({
bootstrap: [
"https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.4.1/js/bootstrap.min.js",
"https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.4.1/css/bootstrap.css",
"https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.6.0/js/bootstrap.bundle.min.js",
"https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.6.0/css/bootstrap.min.css"
]
});
//async await
const packageInstance = await require('packageName(@)(^)(~)(*)(version)(.filetype)');
//mulitple packages
const [pckg1, packg2] = await require([
'pckg1(@)(^)(~)(*)(version)(.filetype)',
'pckg2(@)(^)(~)(*)(version)(.filetype)'
]);
//cjs style (only works when a package is already loaded once, or in a defined factory)
const packageInstance = require('packageName(@)(^)(~)(*)(version)(.filetype)');
//using promises
requirees('packageName(@)(^)(~)(*)(version)(.filetype)').then(packageInstance);
//multiple packages
requirees([
'pckg1(@)(^)(~)(*)(version)(.filetype)',
'pckg2(@)(^)(~)(*)(version)(.filetype)'
]).then(
([pckg1, pckg2]) => {}
);
//using callbacks
require(['packageName(@)(^)(~)(*)(version)(.filetype)'], package => {});
//multiple packages
require([
'pckg1(@)(^)(~)(*)(version)(.filetype)',
'pckg2(@)(^)(~)(*)(version)(.filetype)'
], (pckg1, pckg2) => {});
//without registration
await require(url);
| Key | Description |
|---|---|
| PackageName | the name of the package |
| Version | the version-number in string format: major.minor(.patch)(.build)(-releaseCandidate) |
| Filetype | the file-extension - js/css/txt/xml/json/html/wasm/tag; if no filetype is specified ALL filetypes will be loaded |
Note - Determining the version number happens in this order
- Find best version match, if any versionnumber is specified
- Find the default, if no versionnumber is specified
- Take the highest version number if no default, nor versionnumber are specified
Note - If no filetype is specified all registered filetypes will be loaded
//register bootstrap
require.register({
bootstrap: [
"https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.4.1/js/bootstrap.min.js",
"https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.4.1/css/bootstrap.css",
"https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.6.0/js/bootstrap.bundle.min.js",
"https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.6.0/css/bootstrap.min.css"
]
})
//load both css & js from the highest available version (4.6.0)
//4.6.0 will be the default (no default is set)
const bootstrap = await require('bootstrap');
//4.6.0 is the highest registered version
const bootstrap = await require('bootstrap@*');
//load only the css tag from version 3.4.1
const bootstrapCssTag = await require('bootstrap.css@3.4.1'); //fixed version number
//load only the js tag from version 3.x
const bootstrapJs = await require('bootstrap.js@^3.0.0'); //find highest minor
//try to load bootstrap 3.4.2
const bootstrap = await require('bootstrap@3.4.2');
//will result in a console.warn("package not found");
//version 3.4.2 was not registered using define(), require.register, nor require.config({paths})
//download without registration
const bootstrap = await require('https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.6.0/js/bootstrap.bundle.min.js')
Require-es provides more flexibility on loading multiple versions of a given package.
Unfortunately some amd/umd-packages include predefined dependencies. These can lead to unwanted / unexpected behavior.
###Example: react-dom + react Let's take a look at the conflict below: react 16 + react 18
require.register({
'react': [
'https://cdnjs.cloudflare.com/ajax/libs/react/16.14.0/umd/react.production.min.js',
'https://cdnjs.cloudflare.com/ajax/libs/react-dom/18.0.0/umd/react-dom.production.min.js'
],
'react-dom': [
'https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.14.0/umd/react-dom.production.min.js',
'https://cdnjs.cloudflare.com/ajax/libs/react-dom/18.0.0/umd/react-dom.production.min.js'
]
});
const ReactDom = await require('react-dom@^16.0.0');
//react-dom version 16.14.0 will download/initialize (it's the highest match within major 16)
//react version 18.0.0 will download/initialize...
//this happens because react-dom has a dependency on 'react' baked into the module itself: define(['react'], factoryReactDom(React){})
//see code-snippet below
Why did react 18.0.0 initialize, when react-dom 16.x is required?
The answer can be found in the react-dom source-code itself:
https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.14.0/umd/react-dom.production.min.js
...nction"===typeof define&&define.amd?define(["exports","react"],ea):(I=I||self,ea(I.ReactDOM={},...
Pay close attention to the dependencies set by the react-dom definition: define(["exports","react"]).
This instructs require-es to load "react" (without version number specified) before the "react-dom" factory runs.
If no "react" version is specified, the default version will be loaded (if no default is specified, the highest version becomes the default)
To avoid mixing up versions, require-es allows dependency overrides.
This is done by providing the dependencyOverrides object while registering an amd module.
Syntax
require.register({
packageName: {
url: 'urlToDownloadTheAmdModule',
dependencyOverrides: {
dependencyName: 'newDependencyName(@version)'
}
}
})
Example:
require.register({
'react-dom': [
{
url: 'https://cdnjs.cloudflare.com/ajax/libs/react-dom/18.0.0/umd/react-dom.production.min.js',
dependencyOverrides: { react: 'react@18.0.0' }
},
{
url: 'https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.14.0/umd/react-dom.production.min.js',
dependencyOverrides: { react: 'react@16.14.0' }
}
],
'react': [
'https://cdnjs.cloudflare.com/ajax/libs/react-dom/18.0.0/umd/react-dom.production.min.js',
'https://cdnjs.cloudflare.com/ajax/libs/react/16.14.0/umd/react.production.min.js'
]
});
This will override any hardcoded dependency on "react" to "react@18.0.0" (or "react@16.14.0") in both react-dom packages.
The react-dom factory will now receive a matching react-version.
Looking back at the react-dom source code:
https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.14.0/umd/react-dom.production.min.js
...nction"===typeof define&&define.amd?define(["exports","react"],ea):(I=I||self,ea(I.ReactDOM={},...
//will become
...nction"===typeof define&&define.amd?define(["exports","react@16.14.0"],ea):(I=I||self,ea(I.ReactDOM={},...
https://cdnjs.cloudflare.com/ajax/libs/react-dom/18.0.0/umd/react-dom.production.min.js
...nction"===typeof define&&define.amd?define(["exports","react"],eb):(M=M||self,eb(M.ReactDOM={},...
//will become
...nction"===typeof define&&define.amd?define(["exports","react@18.0.0"],eb):(M=M||self,eb(M.ReactDOM={},...
By default requirees will always try to download a package, even when no registration/definition is available.
Example
require('myUnkownPackage')
//tries to download './myUnkownPackage.js'.
Require.when() ensures the requested package are explicitly defined/registered! If the requested package is not defined/registered yet, require.when will wait for an explicit define/register.
//wait for a single package to get defined/registered
require.when('packageName(@)(^)(~)(*)(version)(.filetype)').then(packageInstance => {});
//wait for multiple packages to get defined/registered
require.when([
'pckg1(@)(^)(~)(*)(version)(.filetype)',
'pckg2(@)(^)(~)(*)(version)(.filetype)'
]).then((pckg1, pckg2) => {});
//using callbacks instead of promises
require.when('packageName(@)(^)(~)(*)(version)(.filetype)', callback, failCallback)
require.when('myUnkownPackage')
.then(p => console.log('my unknown package is defined now', p))
//waits until someone explicitly defines the package
//the promise above will resolve with the 'myUnknownPackage'-exports after 5 seconds
setTimeout(
() => define('myUnkownPackage', () => exports),
5000
);
require.when('three@^0.100.0')
.then(three => console.log('three is registered and usable now', three))
//waits until someone explicitly registers the package
//
setTimeout(
() => require.register({
three: "https://cdnjs.cloudflare.com/ajax/libs/three.js/0.148.0/three.min.js"
}),
5000
);
//named define
define(packageName(@)(version)(.filetype)(-default), [dependencies], factory);
//anonymous define
define([dependencies], factory);
| Key | Description |
|---|---|
| PackageName | the name of the package |
| Version | the version-number in string format: major.minor(.patch)(.build)(-releaseCandidate) |
| Filetype | the file extension - js/css/txt/xml/json/html/wasm/tag |
| Default | indicates the default version |
| Dependencies | package names (or urls) on which this package is dependent |
| Factory | function / json / text / HTMLElement / xml / ... |
Note - The dependency naming rules are equal to the require naming rules:
packageName(@)(^)(~)(*)(version)(.filetype)
Note - The datatype of the factory can be different, depending on the filetype:
- js: function
- json: json-text (gets converted to JSON) / json-object
- css: css-text (gets converted to a script-tag)
- txt: text
- xml: text
- html: html-text (gets converted to an HTMLElement) / HTMLElement-object
//define an amd module
define('hello.js', ['react@^16.0.0'], (react) => {
function fn1(){}
return {fn1}
});
//define a CJS module
define('hello.js', [], () => {
const react = require('react');
function fn1(){}
module.exports = {fn1};
});
//define a json object
define('hello.json', [], '{"foo": "bar"}');
//define css
define('hello.css', [], 'body{background-color: red}');
//define a specific version of hello.css
define('hello.css@1.0.0', [], 'body{background-color: red}');
//define an html fragment
//gets converted to an HTMLElement when required + will automatically add the CSS to the page
define('hello.html', ['hello.css@^1.0.0'], '<div>bla</div>');
//alternative
define('hello.html', [], document.createElement('div'));
//define r.js style
define('react', reactFactoryFn);
//using version number
define('react@17.0.2', react1702FactoryFn);
require.config({
allowRedefine: false,
invokeNonMatchedDefines: true
});
| Key | Description |
|---|---|
| allowRedefine | default: false; false: you cannot change the factory, for a given package (after it gets required for the first time) true: the factory can be changed at any time, next require will use the new factory |
| invokeNonMatchedDefines | default: false; automatically invoke anonymous defines which could not be matched to any package in the RequireEs register. |
//subscribe to an event
require.on(evtName, callback);
//require.subscribe is a synonym for require.on
require.subscribe(evtName, callback);
//publish an event
require.publish(evtName, payload);
//spy on all events
require.addWireTap(callback);
| Event | Trigger |
|---|---|
| requirees.pre-define | when define gets called, but the factory is not stored into the registry yet |
| requirees.define | when a package factory was added to the registry |
| requirees.pre-register | when require.register or require.config({paths}) are called, but the package it not added to the registry yet |
| requirees.register | when a package was added to the registry |
| requirees.pre-file-load | before an actual file/factory load is happening |
| requirees.file-load | when a file/factory load has completed |
| requirees.wiretaps | on all events |
| requirees.scripttag.preadd | triggers before requirees appends a script-tag to the dom |
| requirees.scripttag.added | tiggers after requirees appended a script-tag to the dom |
| requirees.styletag.preadd | triggers before requirees appends a script-tag to the dom |
| requirees.styletag.added | tiggers after requirees appended a style-tag to the dom |
//listen to all files being loaded
requirees.subscribe('requirees.pre-file-load', ({package}) => {
console.log(`start loading package: ${package.name}`);
})
//listen to all events being triggered
requirees.addWireTap(console.log);
//alternative:
requirees.subscribe('requirees.wiretaps', console.log);
//create custom events
requirees.subscribe('hendrik.sayHello', data => {
console.log('hello!!', data)
});
requirees.publish('hendrik.sayHello', {foo: 'bar'});
In the examples below project-dependencies 'jquery', 'react' and 'lodash' will be removed from your bundle and loaded using RequireEs.
To make this happen:
Samples for Webpack and Rollup bundling can be found in the sections below.
//require the AMD module
require.register({
jquery: 'https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.0/jquery.min.js',
react: [
'https://cdnjs.cloudflare.com/ajax/libs/react/17.0.2/umd/react.production.min.js',
'https://cdnjs.cloudflare.com/ajax/libs/react/16.14.0/umd/react.production.min.js',
'https://cdnjs.cloudflare.com/ajax/libs/react/16.10.1/umd/react.production.min.js'
],
lodash: [
'https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js',
'https://cdnjs.cloudflare.com/ajax/libs/lodash.js/3.10.1/lodash.min.js'
]
});
//require the application package
await require('/scripts/myLib.amd.js');
If your package is added through a script-tag, call require.config({invokeNonMatchedDefines: true}) to invoke the factory immediately:
<script>
requirees.config({
invokeNonMatchedDefines: true
})
</script>
<script src="/scripts/myLib.amd.js"></script>
module.exports = {
//...
output: {
libraryTarget: 'amd',
filename: 'scripts/myLib.amd.js'
},
//...
externals: {
jquery: 'jquery@*',
react: 'react@^17.0.0',
lodash: 'lodash@^4.17.0'
},
};
export default {
//...
output: {
format: 'amd',
file: 'scripts/myLib.amd.js',
external: ['react', 'jquery', 'lodash'],
paths: {
react: 'react@^17.0.0',
jquery: 'jquery@*',
lodash: 'lodash@^4.17.0'
}
},
//...
};
module.exports = {
//...
output: {
libraryTarget: 'umd',
filename: 'scripts/myLib.amd.js',
library: 'myLib'
},
//...
externals: {
jquery: {
root: '$',
amd: 'jquery@*',
commonjs: 'jquery',
commonjs2: 'jquery'
},
react: {
root: 'React',
amd: 'react@^17.0.0',
commonjs: 'react',
commonjs2: 'react'
},
lodash: {
root: '_',
amd: 'lodash@^4.17.0',
commonjs: 'lodash',
commonjs2: 'lodash'
}
},
};
export default {
//...
output: {
format: 'umd',
file: 'scripts/myLib.amd.js',
name: 'myLib',
external: ['react', 'jquery', 'lodash'],
paths: {
react: 'react@^17.0.0',
jquery: 'jquery@*',
lodash: 'lodash@^4.17.0'
},
globals: {
react: 'React',
jquery: '$',
lodash: '_'
}
},
//...
};
FAQs
Simple AMD module loader with version support
The npm package requirees receives a total of 258 weekly downloads. As such, requirees popularity was classified as not popular.
We found that requirees demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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