TypeScript in 10 Minutes: From JavaScript to Type Safety

You know JavaScript. TypeScript is just JavaScript with types. Here's everything you need to start. Why bother with TypeScript? // JavaScript — no errors until runtime function greet ( user ) { return `Hello, ${ user . nme } ` ; // typo! "nme" instead of "name" } greet ({ name : " Alice " }); // Returns "Hello, undefined" — silent bug! // TypeScript — catches errors at compile time function greet ( user : { name : string }): string { return `Hello, ${ user . nme } ` ; // Error: Property 'nme' does not exist } TypeScript catches bugs before you run the code. That's the whole deal. Setup in 30 seconds npm install -D typescript tsx @types/node # tsconfig.json npx tsc --init Or use TypeScript directly with Node: npx tsx my-file.ts The 8 types you'll use 90% of the time // 1. Primitives let name : string = " Alice " ; let age : number = 28 ; let active : boolean = true ; // 2. Arrays let tags : string [] = [ " ts " , " js " ]; let scores : number [] = [ 95 , 87 , 92 ]; let mixed : ( string