inject-mutation.test-d.ts

import { describe, expectTypeOf, test } from 'vitest'
import { sleep } from '@tanstack/query-test-utils'
import { injectMutation } from '..'
import type { Signal } from '@angular/core'

describe('injectMutation', () => {
  describe('Discriminated union return type', () => {
    test('data should be possibly undefined by default', () => {
      const mutation = injectMutation(() => ({
        mutationFn: () => sleep(0).then(() => 'string'),
      }))

      expectTypeOf(mutation.data).toEqualTypeOf<Signal<string | undefined>>()
    })

    test('data should be defined when mutation is success', () => {
      const mutation = injectMutation(() => ({
        mutationFn: () => sleep(0).then(() => 'string'),
      }))

      if (mutation.isSuccess()) {
        expectTypeOf(mutation.data).toEqualTypeOf<Signal<string>>()
      }
    })

    test('error should be null when mutation is success', () => {
      const mutation = injectMutation(() => ({
        mutationFn: () => sleep(0).then(() => 'string'),
      }))

      if (mutation.isSuccess()) {
        expectTypeOf(mutation.error).toEqualTypeOf<Signal<null>>()
      }
    })

    test('data should be undefined when mutation is pending', () => {
      const mutation = injectMutation(() => ({
        mutationFn: () => sleep(0).then(() => 'string'),
      }))

      if (mutation.isPending()) {
        expectTypeOf(mutation.data).toEqualTypeOf<Signal<undefined>>()
      }
    })

    test('error should be defined when mutation is error', () => {
      const mutation = injectMutation(() => ({
        mutationFn: () => sleep(0).then(() => 'string'),
      }))

      if (mutation.isError()) {
        expectTypeOf(mutation.error).toEqualTypeOf<Signal<Error>>()
      }
    })

    test('should narrow variables', () => {
      const mutation = injectMutation(() => ({
        mutationFn: (_variables: string) => sleep(0).then(() => 'string'),
      }))

      if (mutation.isIdle()) {
        expectTypeOf(mutation.variables).toEqualTypeOf<Signal<undefined>>()
      }
      if (mutation.isPending()) {
        expectTypeOf(mutation.variables).toEqualTypeOf<Signal<string>>()
      }
      if (mutation.isSuccess()) {
        expectTypeOf(mutation.variables).toEqualTypeOf<Signal<string>>()
      }
      expectTypeOf(mutation.variables).toEqualTypeOf<
        Signal<string | undefined>
      >()
    })
  })
})