How to set up Typescript with Express JS

Today I'm going to show you how to create an Express js project with Typescript as fast as possible.

follow these steps:

• Create the project folder and navigate to it by running the following commands:
  mkdir express-typescript
cd express-typescript

• Initiate the project:
  npm init -y

• Install these dev dependencies (Note the -D flag)
  npm i typescript ts-node @types/node @types/express -D

Your package.json should have this inside:

"devDependencies": {
    "@types/express": "^4.17.9",
    "@types/node": "^14.14.20",
    "ts-node": "^9.1.1",
    "typescript": "^4.1.3"
  },

• Now initialize typescript:
  npx tsc --init
  the command will create a tsconfig.json file. The file will contain the configuration for typescript. The ones we're interested in are:

• target: this specifies wich ECMAScript version is used in your project, default to es2016

• module: specifies which module is used to generate javascript code, defaults to commonjs, You can choose each of this: none, commonjs, es2015, es2020, or ESNext.

• outDir: specifies the output location of the vanilla javascript code. It's commonly used to place it inside the build folder: "outDir": "/build/"

• rootDir: specifies the location of the typescript code, default to ./

• strict: enable/disable the strict mode, default to true

You're now done ! after you finish your project you can run the command npx tsc.

Alternatively , You can create a script to run the command, In your package.json inside the scripts object type:

"scripts": {
    "build": "npx tsc"
}

I hope this post was helpful. Happy coding!