What is ts-loader?
The ts-loader package is a TypeScript loader for webpack that allows you to transpile TypeScript files (.ts, .tsx) to JavaScript while bundling with webpack. It enables you to integrate TypeScript into your webpack build process.
What are ts-loader's main functionalities?
Transpilation of TypeScript to JavaScript
This feature allows you to compile TypeScript files into JavaScript, enabling you to use TypeScript in your webpack projects. The code sample shows a webpack configuration that uses ts-loader to process files with .ts or .tsx extensions.
module.exports = {
mode: 'development',
entry: './src/index.ts',
module: {
rules: [
{
test: /\.tsx?$/,
use: 'ts-loader',
exclude: /node_modules/
}
]
},
resolve: {
extensions: ['.tsx', '.ts', '.js']
},
output: {
filename: 'bundle.js',
path: path.resolve(__dirname, 'dist')
}
};
Integration with webpack's watch mode
ts-loader works seamlessly with webpack's watch mode, which recompiles your code when changes are detected. This feature is useful for development as it provides a fast feedback loop.
webpack --watch
Source map support
ts-loader supports the generation of source maps, which help in debugging by mapping the compiled code back to the original TypeScript source code. The code sample shows how to enable inline source maps in your webpack configuration.
module.exports = {
devtool: 'inline-source-map',
// ... other webpack configuration
};
Other packages similar to ts-loader
awesome-typescript-loader
Similar to ts-loader, awesome-typescript-loader is another TypeScript loader for webpack. It offers features like Babel integration and type checking in a separate process. However, it is no longer actively maintained, and users are recommended to switch to ts-loader or other alternatives.
babel-loader
While not a TypeScript-specific loader, babel-loader can be used in conjunction with @babel/preset-typescript to transpile TypeScript code. It is part of the Babel ecosystem and is often used for its broader transformation capabilities and plugin ecosystem.
esbuild-loader
esbuild-loader uses the esbuild bundler to transpile TypeScript (and other files) at a much faster rate than traditional loaders. It is known for its speed and efficiency, making it a strong alternative to ts-loader, especially in large projects where build time is a concern.
TypeScript loader for webpack
Usage
Installation
npm install ts-loader
Configuration
module.exports = {
entry: './app.ts',
resolve: {
extensions: ['', '.webpack.js', '.web.js', '.js', '.ts']
},
module: {
loaders: [
{ test: /\.ts$/, loader: 'ts-loader' }
]
}
}
Declaration files
All declaration files should be resolvable from the entry file. The easiest way
to do this is to create a _references.d.ts
file which contains references to
all of your declaration files. Then reference _references.d.ts
from your
entry file.
_references.d.ts
///<reference path="path/to/declaration.d.ts" />
///<reference path="path/to/another/declaration.d.ts" />
app.ts
///<reference path="path/to/_references.d.ts" />
import MyClass = require('./MyClass');
...
Loading other resources and code splitting
Loading css and other resources is possible but you will need to make sure that
you have defined the require
function in a declaration file.
declare var require: {
<T>(path: string): T;
(paths: string[], callback: (...modules: any[]) => void): void;
ensure: (paths: string[], callback: (require: <T>(path: string) => T) => void) => void;
};
Then you can simply require assets or chunks per the webpack documentation.
require('!style!css!./style.css');
React JSX
Please see selective-jsx-loader
License
The MIT License (MIT)
Copyright (c) 2015 James Brantly
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.