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typeof

In a type position, derives a type from the type of a runtime value.

Since TS 1.0 Spec ↗

Syntax

typeof value

Examples

const settings = { dark: true, level: 3 };
type Settings = typeof settings;
// { dark: boolean; level: number }

function makeApi() {
  return { get() {}, post() {} };
}
type Api = ReturnType<typeof makeApi>;

Notes

The type-level `typeof` is distinct from the runtime `typeof` operator. It captures the inferred type of a variable, function, or class value, often combined with `keyof`, `ReturnType`, or `InstanceType`. Use `as const` first to capture literal types.

See also