Why Learn TypeScript?

Three practical reasons teams adopt TypeScript over plain JavaScript:

• Catches bugs before runtime — a typo'd property name or a function called with the wrong argument type is flagged immediately, not discovered by a user in production.
• Makes large codebases navigable — your editor can reliably tell you every place a function is called, what shape an object has, and autocomplete its properties, because the types describe it exactly.
• Safer refactoring — renaming a property or changing a function's signature immediately highlights every place that needs updating, instead of hoping you found them all by searching text.

See What Can You Build With TypeScript? below — anywhere you'd use JavaScript, you can use TypeScript instead.