Use when defining global types. Use when augmenting window. Use when typing environment variables. Use when working with build-time constants. Use when configuring type definitions.
Use when migrating JavaScript to TypeScript. Use when gradually adopting TypeScript. Use when working with mixed codebases. Use when converting large projects. Use when teams are learning TypeScript.
Use when writing asynchronous code. Use when tempted to use callbacks. Use when composing multiple async operations.
Use when creating types from example data. Use when types don't match all cases. Use when API responses vary.
Use when writing type annotations on variables. Use when TypeScript can infer the type. Use when code feels cluttered with types.
Use when defining array-like types. Use when tempted to use number as index type. Use when understanding array keys.
Use when functions have multiple parameters of same type. Use when parameter order is easy to confuse. Use when designing function signatures.
Use when writing generic functions or types. Use when reviewing type signatures. Use when a type parameter only appears once. Use when tempted to add generics for "flexibility".