Mocking a Fake Request

Here is a simple function that mocks a fake request with a random delay between 500ms and 2000ms. This can be useful for testing asynchronous code or simulating network requests in JavaScript or TypeScript.

The idea is simple: use setTimeout to resolve a promise after a random delay. The random function generates a random number between the given range, and useFakeRequest returns a promise that resolves with the provided data after that delay.

const random = (min: number, max: number): number => Math.floor(Math.random() * (max - min) + min)

interface FakeRequestOptions {
  timeout?: number
  status?: number
}

interface FakeResponse<T> {
  data: T
  status: number
  statusText: string
  headers: Record<string, string>
}

function useFakeRequest<T>(data: T, options?: FakeRequestOptions): Promise<FakeResponse<T>> {
  const { timeout = random(500, 2000), status = 200 } = options || {}

  const statusText = status === 200 ? 'OK' : 'Internal Server Error'

  return new Promise((resolve) => {
    setTimeout(() => {
      const fakeResponse: FakeResponse<T> = {
        data,
        status,
        statusText,
        headers: {
          'Content-Type': 'application/json',
        },
      }

      return resolve(fakeResponse)
    }, timeout)
  })
}