What is TypeScript?
TypeScript is a superset of JavaScript that adds static type annotations, checked at compile time before the code is transpiled down to plain JavaScript. Types catch a whole class of bugs (wrong argument types, typos in property names) before code ever runs, which is why most large-scale JavaScript codebases have adopted it.
Example
function add(a: number, b: number): number { return a + b; } — types on parameters and return value.
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