Convert existing JavaScript project to support TypeScript

1. Install typescript

pnpm add -D typescript @types/node ts-node

2. Create TypeScript config file

npx tsc --init

And after that, you can use the following config:

{
  "compilerOptions": {
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "target": "ES2020",
    "skipLibCheck": true,
    "useDefineForClassFields": true,
    "lib": ["ES2020", "DOM", "DOM.Iterable"],
    "module": "ESNext",
    "outDir": "dist",
    "allowJs": true,
    "incremental": true,

    /* Bundle mode */
    "moduleResolution": "Bundler",
    "allowImportingTsExtensions": true,
    "resolveJsonModule": true,
    "noEmit": true,
    "isolatedModules": true,

    /* Linting */
    "strict": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noFallthroughCasesInSwitch": true,

    /* Path */
    "baseUrl": ".",
    "paths": {
      "@/*": ["./src/*"]
    }
  },
  "include": ["src"],
  "exclude": ["node_modules", "dist"]
}

3. Update package.json

package.json

{
  ...
  "scripts": {
		"compile": "npx tsc -p ./",
		"watch": "npx tsc -watch -p ./"
	}
  ...
}