What is this?
This repo provides a script that will automatically configure SystemJS to use TypeScript and Babel to transpile your TypeScript/ES6/ES2015 code to ES5 code directly in the browser, all without a development build step. This gives you easy access to all TypeScript and ES6/ES2015 features, including ES6 modules and the amazing async/await.
Installation
npm install --save es-no-build
Basic Usage
To immediately get started just include this repo's config.js file in your index.html:
<!--index.html-->
<!DOCTYPE html>
<html>
<head>
<script src="node_modules/es-no-build/config.js"></script>
</head>
<body>
<script>
System.import('main-code.js');
</script>
</body>
</html>
You can put any TypeScript/ES6/ES2015 code and any Stage 2 or Stage 3 features code in the file that you import:
//main-code.js
import {testFunction} from 'test-module.js';
console.log(testFunction());
SystemJS automatically follows all of your imports and transpiles everything:
//test-module.js
const asyncFunction = async () => {
return 'this is the result of the async function';
};
export const testFunction = async () => {
return await asyncFunction();
};
If you need to know exactly what is going on during transpilation, including what type of code is accepted, see the following resources:
Custom Usage
Type Checking
Basic usage as described above will transpile and run TypeScript/ES6/ES2015 code, but it will not perform type checking. If you would like the results of type checking to be logged to the console, include the add-type-check.js script anywhere before the config.js script:
<head>
<script src="node_modules/es-no-build/add-type-check.js"></script>
<script src="node_modules/es-no-build/config.js"></script>
</head>
tsconfig.json
If you would like to add TypeScript configuration through a tsconfig.json file, then make sure the file is available from your server's root endpoint, and then include the add-tsconfig.js script anywhere before the config.js script:
<head>
<script src="node_modules/es-no-build/add-type-check.js"></script>
<script src="node_modules/es-no-build/add-tsconfig.js"></script>
<script src="node_modules/es-no-build/config.js"></script>
</head>
Special Considerations
Deduplication
This repo assumes a flat dependency hierarchy. If you did not install this repo with a version of npm that installs dependencies flatly, then running the following command should fix it (be careful though, you might break other dependencies, I would upgrade to the latest version of npm if possible):
npm dedupe
node_modules and tsconfig.json locations
This repo assumes that your node_modules directory and tsconfig.json file are located at the root endpoint of your server. If this does not work for you, you can edit the paths in config.js temporarily. You should then open an issue so that I can consider the options.
Production
Unfortunately, because of the time it takes to transpile and follow all of the imports in your code in the browser, you will probably want to use a build step for production deployment of your application. This repo solves the problem of the complexity of the development build step, with the price of slowness. It will make the initial load of your application slow. How slow? It depends on the structure of your imports and the amount of code you have. This repo can be used to keep development simple, but production will need a build step. I'll work on a simple way to use SystemJS to bundle and transpile all of your files for production, I just haven't look too much into it yet.
Motivations
What is the problem?
Have you ever wanted to use ES6/ES2015? Have you ever wanted to use TypeScript? What about async/await? Of course you have. Unfortunately, most web browsers don't natively support all of the JavaScript features that we want...yet. So, to get around that slight limitation, people have created webpack, Babel, TypeScript, Traceur, etc. Unfortunately again, adding these technologies adds complexity to our development environments, including a "build step". What if you don't want a development build step? This repo helps solve that problem.
How is it solved?
Using SystemJS along with a SystemJS TypeScript plugin and a SystemJS Babel plugin, SystemJS will take care of following and importing from all imports in our code, and will transpile our code from TypeScript to ES6/ES2015 to ES5.
Why is this nice?
No more webpack. No more browserify. No more installing TypeScript, and Babel, and Babel presets, and Babel plugins, and including the Babel polyfill to get async/await to work. Just include SystemJS and this repo's config.js file, and all of the transpilation and polyfilling is done for you in the browser. Nice!