Blame view

node_modules/vue/src/core/components/keep-alive.ts 4.17 KB
4cd4fd28   郭伟龙   feat: 初始化项目
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
import { isRegExp, isArray, remove } from 'shared/util'
import { getFirstComponentChild } from 'core/vdom/helpers/index'
import type VNode from 'core/vdom/vnode'
import type { VNodeComponentOptions } from 'types/vnode'
import type { Component } from 'types/component'
import { getComponentName } from '../vdom/create-component'

type CacheEntry = {
  name?: string
  tag?: string
  componentInstance?: Component
}

type CacheEntryMap = Record<string, CacheEntry | null>

function _getComponentName(opts?: VNodeComponentOptions): string | null {
  return opts && (getComponentName(opts.Ctor.options as any) || opts.tag)
}

function matches(
  pattern: string | RegExp | Array<string>,
  name: string
): boolean {
  if (isArray(pattern)) {
    return pattern.indexOf(name) > -1
  } else if (typeof pattern === 'string') {
    return pattern.split(',').indexOf(name) > -1
  } else if (isRegExp(pattern)) {
    return pattern.test(name)
  }
  /* istanbul ignore next */
  return false
}

function pruneCache(
  keepAliveInstance: { cache: CacheEntryMap; keys: string[]; _vnode: VNode },
  filter: Function
) {
  const { cache, keys, _vnode } = keepAliveInstance
  for (const key in cache) {
    const entry = cache[key]
    if (entry) {
      const name = entry.name
      if (name && !filter(name)) {
        pruneCacheEntry(cache, key, keys, _vnode)
      }
    }
  }
}

function pruneCacheEntry(
  cache: CacheEntryMap,
  key: string,
  keys: Array<string>,
  current?: VNode
) {
  const entry = cache[key]
  if (entry && (!current || entry.tag !== current.tag)) {
    // @ts-expect-error can be undefined
    entry.componentInstance.$destroy()
  }
  cache[key] = null
  remove(keys, key)
}

const patternTypes: Array<Function> = [String, RegExp, Array]

// TODO defineComponent
export default {
  name: 'keep-alive',
  abstract: true,

  props: {
    include: patternTypes,
    exclude: patternTypes,
    max: [String, Number]
  },

  methods: {
    cacheVNode() {
      const { cache, keys, vnodeToCache, keyToCache } = this
      if (vnodeToCache) {
        const { tag, componentInstance, componentOptions } = vnodeToCache
        cache[keyToCache] = {
          name: _getComponentName(componentOptions),
          tag,
          componentInstance
        }
        keys.push(keyToCache)
        // prune oldest entry
        if (this.max && keys.length > parseInt(this.max)) {
          pruneCacheEntry(cache, keys[0], keys, this._vnode)
        }
        this.vnodeToCache = null
      }
    }
  },

  created() {
    this.cache = Object.create(null)
    this.keys = []
  },

  destroyed() {
    for (const key in this.cache) {
      pruneCacheEntry(this.cache, key, this.keys)
    }
  },

  mounted() {
    this.cacheVNode()
    this.$watch('include', val => {
      pruneCache(this, name => matches(val, name))
    })
    this.$watch('exclude', val => {
      pruneCache(this, name => !matches(val, name))
    })
  },

  updated() {
    this.cacheVNode()
  },

  render() {
    const slot = this.$slots.default
    const vnode = getFirstComponentChild(slot)
    const componentOptions = vnode && vnode.componentOptions
    if (componentOptions) {
      // check pattern
      const name = _getComponentName(componentOptions)
      const { include, exclude } = this
      if (
        // not included
        (include && (!name || !matches(include, name))) ||
        // excluded
        (exclude && name && matches(exclude, name))
      ) {
        return vnode
      }

      const { cache, keys } = this
      const key =
        vnode.key == null
          ? // same constructor may get registered as different local components
            // so cid alone is not enough (#3269)
            componentOptions.Ctor.cid +
            (componentOptions.tag ? `::${componentOptions.tag}` : '')
          : vnode.key
      if (cache[key]) {
        vnode.componentInstance = cache[key].componentInstance
        // make current key freshest
        remove(keys, key)
        keys.push(key)
      } else {
        // delay setting the cache until update
        this.vnodeToCache = vnode
        this.keyToCache = key
      }

      // @ts-expect-error can vnode.data can be undefined
      vnode.data.keepAlive = true
    }
    return vnode || (slot && slot[0])
  }
}