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Why Companies Use It
Why Teams Choose TypeScript
- Fewer production bugs: wrong types, missing properties and
undefinedaccess are caught early. - Self-documenting code: the function signature tells you what to pass and what you get back.
- Safe refactoring: rename a field and the compiler lists every file that must change.
- Better tooling: autocomplete for your own objects and for libraries.
- Easier onboarding: new developers understand big codebases faster.
Who Uses TypeScript
| Company / Product | Where |
|---|---|
| Microsoft | VS Code is written in TypeScript |
| Slack, Airbnb, Stripe | migrated large JavaScript codebases to TypeScript |
| Angular | the framework itself and all Angular apps use TypeScript |
| Next.js, NestJS | TypeScript is the default for new projects |
| Indian startups | Razorpay, Swiggy, Zomato, CRED, Meesho use TypeScript in web and Node.js services |
Tip: Most React, Next.js and Node.js job descriptions in India now list TypeScript as required or preferred. It is one of the most loved languages in the Stack Overflow survey every year.
A Bug TypeScript Prevents
Example
An API sometimes returns no discount. Without types, discount.percent crashes at runtime. With strict mode TypeScript forces you to handle the missing case (error TS18048).
type Discount = { percent: number };
function finalPrice(price: number, discount?: Discount): number {
return price - (price * discount.percent) / 100;
}
console.log(finalPrice(1000));Compiler output (tsc)
Line 4: error TS18048: 'discount' is possibly 'undefined'.