TypeScript

Formally, the type system in TypeScript is unsound:

function add(x: number, y: number) { return x + y; }
let arr = [1, 2, 3];
add(arr[3], arr[4]);
// typechecks, but fails at a runtime
// can be improved with `noUncheckedIndexedAccess` option

Learning

TypeHero

Tools

Knip | knip.dev – find unused files, dependencies and exports in JavaScript and TypeScript projects
TypeScript Explorer - Visual Studio Marketplace

Compiler

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