Setting up a new TypeScript project

Node.js

  1. Create a new npm project

    1. Create a new directory and cd into it

    2. Initialize a new npm project

      npm init
      
  2. Install ts-node and typescript

    npm i ts-node typescript
    
  3. Create tsconfig.json

    npx tsc --init
    
    • If you forget this step, you may get weird TypeScript errors, such as

      Cannot find name 'require'.
      
  4. Update package.json

    • Update references to files with .js extensions, e.g.

      "main": "app.ts"
      

      (Even if this is a fresh TypeScript project, you may have references to .js files depending on how you used npm init)

    • Update anything in scripts using node to use ts-node, e.g.

      From:

      "start": "node ."
      

      To:

      "start": "ts-node ."
      

Troubleshooting

Cannot find module '...' or its corresponding type declarations.

If you’re using TypeScript with Node.js:

  1. Make sure you have the Node types package installed:

    npm i --save-dev @types/node
    
  2. If you still get the error and you don’t have a tsconfig.json file, generate one:

    npx -p typescript tsc --init