type predicate

@nick/is/type/predicate

Predicate

Signature

export type Predicate<
  Type extends Base = any,
  Base = unknown,
  Args extends readonly unknown[] = any[],
> = Expand<(it: Base, ...args: Args) => it is Type>;

Represents a type guard (predicate function) that checks if a given value of the base type Base is also of the derived type Type.

Type Parameters

• Type extends Base (default: any)
• Base (default: unknown)
• Args extends readonly unknown[] (default: any[])

---

Examples

const isString: Predicate<string> = (it: unknown): it is string => (
  typeof it === "string"
);