Mocking 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.

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

const random = (min, max) => 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)
  })
}