core/packages/reactivity/__tests__/ref.spec.ts

import { ref, effect, reactive, isRef, toRefs, Ref } from '../src/index'
import { computed } from '@vue/runtime-dom'

describe('reactivity/ref', () => {
  it('should hold a value', () => {
    const a = ref(1)
    expect(a.value).toBe(1)
    a.value = 2
    expect(a.value).toBe(2)
  })

  it('should be reactive', () => {
    const a = ref(1)
    let dummy
    effect(() => {
      dummy = a.value
    })
    expect(dummy).toBe(1)
    a.value = 2
    expect(dummy).toBe(2)
  })

  it('should make nested properties reactive', () => {
    const a = ref({
      count: 1
    })
    let dummy
    effect(() => {
      dummy = a.value.count
    })
    expect(dummy).toBe(1)
    a.value.count = 2
    expect(dummy).toBe(2)
  })

  it('should work without initial value', () => {
    const a = ref()
    let dummy
    effect(() => {
      dummy = a.value
    })
    expect(dummy).toBe(undefined)
    a.value = 2
    expect(dummy).toBe(2)
  })

  it('should work like a normal property when nested in a reactive object', () => {
    const a = ref(1)
    const obj = reactive({
      a,
      b: {
        c: a
      }
    })

    let dummy1: number
    let dummy2: number

    effect(() => {
      dummy1 = obj.a
      dummy2 = obj.b.c
    })

    const assertDummiesEqualTo = (val: number) =>
      [dummy1, dummy2].forEach(dummy => expect(dummy).toBe(val))

    assertDummiesEqualTo(1)
    a.value++
    assertDummiesEqualTo(2)
    obj.a++
    assertDummiesEqualTo(3)
    obj.b.c++
    assertDummiesEqualTo(4)
  })

  it('should unwrap nested ref in types', () => {
    const a = ref(0)
    const b = ref(a)

    expect(typeof (b.value + 1)).toBe('number')
  })

  it('should unwrap nested values in types', () => {
    const a = {
      b: ref(0)
    }

    const c = ref(a)

    expect(typeof (c.value.b + 1)).toBe('number')
  })

  it('should NOT unwrap ref types nested inside arrays', () => {
    const arr = ref([1, ref(1)]).value
    ;(arr[0] as number)++
    ;(arr[1] as Ref<number>).value++

    const arr2 = ref([1, new Map<string, any>(), ref('1')]).value
    const value = arr2[0]
    if (isRef(value)) {
      value + 'foo'
    } else if (typeof value === 'number') {
      value + 1
    } else {
      // should narrow down to Map type
      // and not contain any Ref type
      value.has('foo')
    }
  })

  it('should keep tuple types', () => {
    const tuple: [number, string, { a: number }, () => number, Ref<number>] = [
      0,
      '1',
      { a: 1 },
      () => 0,
      ref(0)
    ]
    const tupleRef = ref(tuple)

    tupleRef.value[0]++
    expect(tupleRef.value[0]).toBe(1)
    tupleRef.value[1] += '1'
    expect(tupleRef.value[1]).toBe('11')
    tupleRef.value[2].a++
    expect(tupleRef.value[2].a).toBe(2)
    expect(tupleRef.value[3]()).toBe(0)
    tupleRef.value[4].value++
    expect(tupleRef.value[4].value).toBe(1)
  })

  test('isRef', () => {
    expect(isRef(ref(1))).toBe(true)
    expect(isRef(computed(() => 1))).toBe(true)

    expect(isRef(0)).toBe(false)
    expect(isRef(1)).toBe(false)
    // an object that looks like a ref isn't necessarily a ref
    expect(isRef({ value: 0 })).toBe(false)
  })

  test('toRefs', () => {
    const a = reactive({
      x: 1,
      y: 2
    })

    const { x, y } = toRefs(a)

    expect(isRef(x)).toBe(true)
    expect(isRef(y)).toBe(true)
    expect(x.value).toBe(1)
    expect(y.value).toBe(2)

    // source -> proxy
    a.x = 2
    a.y = 3
    expect(x.value).toBe(2)
    expect(y.value).toBe(3)

    // proxy -> source
    x.value = 3
    y.value = 4
    expect(a.x).toBe(3)
    expect(a.y).toBe(4)

    // reactivity
    let dummyX, dummyY
    effect(() => {
      dummyX = x.value
      dummyY = y.value
    })
    expect(dummyX).toBe(x.value)
    expect(dummyY).toBe(y.value)

    // mutating source should trigger effect using the proxy refs
    a.x = 4
    a.y = 5
    expect(dummyX).toBe(4)
    expect(dummyY).toBe(5)
  })
})