Vue2

[caroundsky]

JSX

使用slot插槽

// 方案一
<ctreeselect
  scopedSlots = {{
    'value-label': (row) => {
      return (
        <div title={row.node.raw.label}>
          {row.node.raw.label}
        </div>
      )
    }
  }}
/>

// 方案二
<ctreeselect
  {...{
    scopedSlots: {
      'value-label': (row) => {
        return (
          <div title={row.node.raw.label}>
            {row.node.raw.label}
          </div>
        )
      }
    }
  }}
/>

在map中获取ref，如果要获取数组，需要配置refInFor = {true}

使用原生键盘按下事件

nativeOnKeydown={ (e) =>xxx }

[caroundsky]

组件

• vue-treeselect 组件异步获取子节点数据

• el-table fixed 下的expand展开会render多次

• 场景：el-table 合并为一整行 + 树形数据与懒加载

/**
 * 合并整行：不合并的列需要返回[0, 0]
 * colspan: 列长
**/
arraySpanMethod({ row, columnIndex }) {
  if (this.colspan && row.children || row.hasChildren) {
    if (columnIndex === 0) {
      return [1, this.colspan]
    } else {
      return [0, 0]
    }
  }
}

懒加载配合一次性展开时，因为官方的手动方法toggleRowExpansion不支持懒加载，所以需要另寻方案；
提供两个思路：
1、如果只需要单个展开，可获取table store内的指定行后，手动更改其状态
2、如果一次展开多个，上述方法因为异步获取数据，数据无法获取到最新的，所以需要在数据返回后，再执行上述方法。

expendAll() {
  this.expandAll = !this.expandAll
  // hack 因为toggleRowExpansion不支持懒加载，所有手动触发点击事件
  const expandIcons = [...this.tableRef.querySelectorAll('.el-table__expand-icon')]
  expandIcons.forEach(icon => {
    if (this.expandAll && !icon.classList.contains('el-table__expand-icon--expanded')) {
      icon.click()
    }
    if (!this.expandAll && icon.classList.contains('el-table__expand-icon--expanded')) {
      icon.click()
    }
  })
}

async loadTree(tree, treeNode, resolve) {
  const res = await getData(tree.id)

  // 获取el-table内store
  const { store } = this.tableRef
  const { states: { treeData } } = store
  const _data = treeData[tree.id]

  resolve(data)

  // hack 同时展开全部时部分行无法更新状态，手动去store更新
  _data.loaded = true
  _data.loading = false
  _data.expanded = true
},

• el-table 简单封装 el-table-column，以便数据配置化和jsx书写

<el-table xxx>
  <template v-for="(item, index) in tableColumns">
    <VNodes :key="index" :vnodes="renderTableColumn(item)" />
  </template>
<el-table>

components: {
  VNodes: {
    functional: true,
    render: (h: any, ctx: any) => {
      const { vnodes } = ctx.props;
      return typeof vnodes === "object" ? vnodes : <span>{vnodes}</span>;
    },
  },
}

methods: {
  renderTableColumn(columns) {
    const _createColumn = (column) => {
      if (!column.align) {
        column.align = 'center'
      }
      const { render, renderHeader = null, children, ...props } = column
      const VNodeData: any = { props }
      if (render) {

      // 可以操作render，给其外部包裹一些自定义内容
      // let _render = (_col) => {
      //   const prop = props.prop
      //     ? `supplier_info_list.${_col.$index}.${props.prop}`
      //     : null
      //   _col.props = {
      //     disabled: _col.row._disabled,
      //   }
      //   return (
      //     <el-form-item
      //       prop={prop}
      //       key={_col._uuid}
      //       rules={[
      //         {
      //           required: props.required,
      //           message: `请输入${props.label}`,
      //           // trigger: '乱写即可不校验',
      //         },
      //       ]}
      //     >
      //       {render(_col)}
      //     </el-form-item>
      //   )
      // }

        let _renderHeader
        if (renderHeader) {
          _renderHeader = (
            <div>
              {renderHeader(VNodeData)}
              {VNodeData.required && <i class="required" />}
            </div>
          )
        } else {
          _renderHeader = (
            <div>
              {props.label}
              {props.required && <i class="required" />}
            </div>
          )
        }

        VNodeData.scopedSlots = {
          default: (row) => render(row),
          header: () => _renderHeader,
        }
      }
      const VNodeChildren = Array.isArray(children)
        ? children.map((child) => _createColumn(child))
        : null
      return this.$createElement('el-table-column', VNodeData, VNodeChildren)
    }
    return typeof columns === 'object' ? _createColumn(columns) : null
  }
}

• 场景：el-date-picker 设置不可选时间段 :picker-options="pickerOptions"

// 月份区间
pickerOptions() {
  return {
    disabledDate(time) {
      let myDate = new Date()
      let t = myDate.getDate()
      // 如果想包含本月本月 - 8.64e7 * t 就不需要了，
      // 如果想之前的不能选择把 > 换成 <
      return time.getTime() > Date.now() - 8.64e7 * t
    }
  }
}

[caroundsky]

Vue

通过F12的 $0.value 方式修改，触发双向绑定

此时是无法触发的，可通过发射自定义事件解决

(function(){
    $0.value = '1111'
    $0.dispatchEvent(new Event('input'))
})()

[caroundsky]

热加载

问题描述：

在使用keep-alive包裹router时，页面的热更新会导致白屏，同样的问题可参看 https://github.com/vuejs/vue-loader/issues/1332。

问题原因是值在 keep-alive 中的缓存 key 为 router-view 的 key 值，它是不变的，但热更新后组件 cid 会变化。

解决方案：缓存 key的取法 加上cid，并替换原keep-alive组件

import { isRegExp } from 'lodash'
import Vue from 'vue'
/*
 * https://github.com/vuejs/vue-loader/issues/1332#issuecomment-601572625
 */
function isDef(v) {
  return v !== undefined && v !== null
}
function isAsyncPlaceholder(node) {
  return node.isComment && node.asyncFactory
}
function getFirstComponentChild(children) {
  if (Array.isArray(children)) {
    for (var i = 0; i < children.length; i++) {
      var c = children[i]
      if (isDef(c) && (isDef(c.componentOptions) || isAsyncPlaceholder(c))) {
        return c
      }
    }
  }
}
function getComponentName(opts) {
  return opts && (opts.Ctor.options.name || opts.tag)
}
function matches(pattern, name) {
  if (Array.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 remove(arr, item) {
  if (arr.length) {
    var index = arr.indexOf(item)
    if (index > -1) {
      return arr.splice(index, 1)
    }
  }
}
function pruneCacheEntry(cache, key, keys, current) {
  var cached$$1 = cache[key]
  if (cached$$1 && (!current || cached$$1.tag !== current.tag)) {
    cached$$1.componentInstance.$destroy()
  }
  cache[key] = null
  remove(keys, key)
}
function pruneCache(keepAliveInstance, filter) {
  var cache = keepAliveInstance.cache
  var keys = keepAliveInstance.keys
  var _vnode = keepAliveInstance._vnode
  const cachedNameKeyMap = keepAliveInstance.cachedNameKeyMap
  for (var key in cache) {
    var cachedNode = cache[key]
    if (cachedNode) {
      var name = getComponentName(cachedNode.componentOptions)
      if (name && !filter(name)) {
        delete cachedNameKeyMap[name]
        pruneCacheEntry(cache, key, keys, _vnode)
      }
    }
  }
}
const patternTypes = [String, RegExp, Array]
const KeepAlive = {
  name: 'keep-alive',
  abstract: true,

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

  created() {
    this.cache = Object.create(null)
    this.cachedNameKeyMap = Object.create(null)
    this.keys = []
  },
  destroyed() {
    for (const key in this.cache) {
      pruneCacheEntry(this.cache, key, this.keys)
    }
  },
  mounted() {
    this.$watch('include', (val) => {
      pruneCache(this, (name) => matches(val, name))
    })
    this.$watch('exclude', (val) => {
      pruneCache(this, (name) => !matches(val, name))
    })
  },
  render() {
    const slot = this.$slots.default
    const vnode = getFirstComponentChild(slot)
    const componentOptions = vnode && vnode.componentOptions
    if (componentOptions) {
      // check pattern
      const name = getComponentName(componentOptions)
      const { include, exclude } = this
      if (
        // not included
        (include && (!name || !matches(include, name))) ||
        // excluded
        (exclude && name && matches(exclude, name))
      ) {
        return vnode
      }
      const { cache, cachedNameKeyMap, keys } = this
      // 解决方案：处理key值，加上componentOptions.Ctor.cid
      const key = vnode.key
        ? componentOptions.Ctor.cid +
          (componentOptions.tag ? `::${componentOptions.tag}` : '')
        : vnode.key + componentOptions.Ctor.cid

      if (cache[key]) {
        vnode.componentInstance = cache[key].componentInstance
        // make current key freshest
        remove(keys, key)
        keys.push(key)
      } else {
        cache[key] = vnode
        keys.push(key)
        // prune old component for hmr
        if (name && cachedNameKeyMap[name] && cachedNameKeyMap[name] !== key) {
          pruneCacheEntry(cache, cachedNameKeyMap[name], keys)
        }
        cachedNameKeyMap[name] = key
        // prune oldest entry
        if (this.max && keys.length > parseInt(this.max)) {
          pruneCacheEntry(cache, keys[0], keys, this._vnode)
        }
      }
      vnode.data.keepAlive = true
    }
    return vnode || (slot && slot[0])
  },
}
// ovveride original keep-alive
process.env.NODE_ENV === 'development' && Vue.component('KeepAlive', KeepAlive)

[caroundsky]

Vue2 在template中渲染vnode

要在视图中渲染vnode，需要用组件进行中转，比如定义一个函数式组件VNodes，其render函数内返回vnode

<SomeComponent v-slot="{ vnodes }">
  <div>
    <VNodes :vnodes="vnodes"/>
  </div>
</SomeComponent>

components: {
  VNodes: {
    functional: true,
    render: (h, ctx) => ctx.props.vnodes,
  },
},