errorHook.test.ts

import { useState, useEffect } from 'react'
import { renderHook, act } from '..'

describe('error hook tests', () => {
  function useError(throwError?: boolean) {
    if (throwError) {
      throw new Error('expected')
    }
    return true
  }

  function useAsyncError(throwError: boolean) {
    const [value, setValue] = useState<boolean>()
    useEffect(() => {
      const timeout = setTimeout(() => setValue(throwError), 100)
      return () => clearTimeout(timeout)
    }, [throwError])
    return useError(value)
  }

  function useEffectError(throwError: boolean) {
    useEffect(() => {
      useError(throwError)
    }, [throwError])
    return true
  }

  describe('synchronous', () => {
    test('should raise error', () => {
      const { result } = renderHook(() => useError(true))

      expect(() => {
        expect(result.current).not.toBe(undefined)
      }).toThrow(Error('expected'))
    })

    test('should capture error', () => {
      const { result } = renderHook(() => useError(true))

      expect(result.error).toEqual(Error('expected'))
    })

    test('should not capture error', () => {
      const { result } = renderHook(() => useError(false))

      expect(result.current).not.toBe(undefined)
      expect(result.error).toBe(undefined)
    })

    test('should reset error', () => {
      const { result, rerender } = renderHook(({ throwError }) => useError(throwError), {
        initialProps: { throwError: true }
      })

      expect(result.error).not.toBe(undefined)

      rerender({ throwError: false })

      expect(result.current).not.toBe(undefined)
      expect(result.error).toBe(undefined)
    })
  })

  describe('asynchronous', () => {
    test('should raise async error', async () => {
      const { result, waitForNextUpdate } = renderHook(() => useAsyncError(true))

      await waitForNextUpdate()

      expect(() => {
        expect(result.current).not.toBe(undefined)
      }).toThrow(Error('expected'))
    })

    test('should capture async error', async () => {
      const { result, waitForNextUpdate } = renderHook(() => useAsyncError(true))

      await waitForNextUpdate()

      expect(result.error).toEqual(Error('expected'))
    })

    test('should not capture async error', async () => {
      const { result, waitForNextUpdate } = renderHook(() => useAsyncError(false))

      await waitForNextUpdate()

      expect(result.current).not.toBe(undefined)
      expect(result.error).toBe(undefined)
    })

    test('should reset async error', async () => {
      const { result, waitForNextUpdate, rerender } = renderHook(
        ({ throwError }) => useAsyncError(throwError),
        { initialProps: { throwError: true } }
      )

      await waitForNextUpdate()

      expect(result.error).not.toBe(undefined)

      rerender({ throwError: false })

      await waitForNextUpdate()

      expect(result.current).not.toBe(undefined)
      expect(result.error).toBe(undefined)
    })
  })

  describe('effect', () => {
    test('should raise effect error', () => {
      const { result } = renderHook(() => useEffectError(true))

      expect(() => {
        expect(result.current).not.toBe(undefined)
      }).toThrow(Error('expected'))
    })

    test('should capture effect error', () => {
      const { result } = renderHook(() => useEffectError(true))
      expect(result.error).toEqual(Error('expected'))
    })

    test('should not capture effect error', () => {
      const { result } = renderHook(() => useEffectError(false))

      expect(result.current).not.toBe(undefined)
      expect(result.error).toBe(undefined)
    })

    test('should reset effect error', () => {
      const { result, rerender } = renderHook(({ throwError }) => useEffectError(throwError), {
        initialProps: { throwError: true }
      })

      expect(result.error).not.toBe(undefined)

      rerender({ throwError: false })

      expect(result.current).not.toBe(undefined)
      expect(result.error).toBe(undefined)
    })
  })

  describe('error output suppression', () => {
    test('should allow console.error to be mocked', async () => {
      const consoleError = console.error
      console.error = jest.fn()

      try {
        const { rerender, unmount } = renderHook(
          (stage) => {
            useEffect(() => {
              console.error(`expected in effect`)
              return () => {
                console.error(`expected in unmount`)
              }
            }, [])
            console.error(`expected in ${stage}`)
          },
          {
            initialProps: 'render'
          }
        )

        act(() => {
          console.error('expected in act')
        })

        await act(async () => {
          await new Promise((resolve) => setTimeout(resolve, 100))
          console.error('expected in async act')
        })

        rerender('rerender')

        unmount()

        expect(console.error).toBeCalledWith('expected in render')
        expect(console.error).toBeCalledWith('expected in effect')
        expect(console.error).toBeCalledWith('expected in act')
        expect(console.error).toBeCalledWith('expected in async act')
        expect(console.error).toBeCalledWith('expected in rerender')
        expect(console.error).toBeCalledWith('expected in unmount')
        expect(console.error).toBeCalledTimes(6)
      } finally {
        console.error = consoleError
      }
    })
  })
})