Remarks#

To get syntax highlighting in your editor (e.g. VS Code) you’ll need to download typing information for the modules that you use in your project.

Say for example you use React and ReactDOM in your project, and you want to get highlighting and Intellisense for them. You will need to add the types to your project using this command:

npm install --save @types/react @types/react-dom

Your editor should now automatically pick up on on this typing information and supply you with autocomplete and Intellisense for these modules.

webpack.config.js

module.exports = {
    entry: './src/index',
    output: {
        path: __dirname + '/build',
        filename: 'bundle.js'
    },
    module: {
        rules: [{
            test: /\.tsx?$/,
            loader: 'ts-loader',
            exclude: /node_modules/
        }]
    },
    resolve: {
        extensions: ['.ts', '.tsx']
    }
};

The main components are (in addition to the standard entry, output and other webpack properties):

The loader

For this you need to create a rule that tests for the .ts and .tsx file extensions, specify ts-loader as the loader.

Resolve TS extensions

You also need to add the .ts and .tsx extensions in the resolve array, or webpack won’t see them.

tsconfig.json

This is a minimal tsconfig to get you up and running.

{
    "include": [
        "src/*"
    ],
    "compilerOptions": {
        "target": "es5",
        "jsx": "react",
        "allowSyntheticDefaultImports": true
    }
}

Let’s go through the properties one by one:

include

This is an array of source code. Here we have only one entry, src/*, which specifies that everything in the src directory is to be included in compilation.

compilerOptions.target

Specifies that we want to compile to ES5 target

compilerOptions.jsx

Setting this to true will make TypeScript automatically compile your tsx syntax from <div /> to React.createElement("div").

compilerOptions.allowSyntheticDefaultImports

Handy property which will allow you to import node modules as if they are ES6 modules, so instead of doing

import * as React from 'react'
const { Component } = React

you can just do

import React, { Component } from 'react'

without any errors telling you that React has no default export.

My First Component

import React, { Component } from 'react';
import ReactDOM from 'react-dom';


interface AppProps {
    name: string;
}
interface AppState {
    words: string[];
}

class App extends Component<AppProps, AppState> {
    constructor() {
        super();
        this.state = {
            words: ['foo', 'bar']
        };
    }

    render() {
        const { name } = this.props;
        return (<h1>Hello {name}!</h1>);
    }
}

const root = document.getElementById('root');
ReactDOM.render(<App name="Foo Bar" />, root);

When using TypeScript with React, once you’ve downloaded the React DefinitelyTyped type definitions (npm install --save @types/react), every component will require you to add type annotations.

You do this like so:

class App extends Component<AppProps, AppState> { }

where AppProps and AppState are interfaces (or type aliases) for your components’ props and state respectively.