Expectation

Summary

Object returned by expect. Exposes the synchronous matcher set directly on the object, plus the negation and async-resolution gateways needed for full jest/vitest-style assertions.

Signature

interface Expectation {
  not: Matchers;
  rejects: AsyncMatchers;
  resolves: AsyncMatchers;
  toBe(expected: unknown): void;
  toBeCloseTo(n: number, precision: number): void;
  toBeDefined(): void;
  toBeGreaterThan(n: number): void;
  toBeGreaterThanOrEqual(n: number): void;
  toBeInstanceOf(ctor: Function): void;
  toBeLessThan(n: number): void;
  toBeLessThanOrEqual(n: number): void;
  toBeNull(): void;
  toBeTruthy(): void;
  toBeUndefined(): void;
  toContain(item: unknown): void;
  toEqual(expected: unknown): void;
  toHaveBeenCalled(): void;
  toHaveBeenCalledTimes(n: number): void;
  toHaveBeenCalledWith(args: unknown[]): void;
  toHaveBeenNthCalledWith(nth: number, args: unknown[]): void;
  toHaveLength(n: number): void;
  toHaveProperty(key: string, value: unknown): void;
  toMatch(re: string | RegExp): void;
  toMatchObject(expected: object): void;
  toThrow(expected: unknown): void;
}

Properties

not

Negates the next matcher — expect(x).not.toBe(1) passes when x !== 1.

rejects

Awaits the received promise expecting it to reject, then runs the next matcher against the rejection value. Use with await.

resolves

Awaits the received promise expecting it to resolve, then runs the next matcher against the resolved value. Use with await.