bootstrap-vue/src/components/table/helpers/mixin-provider.js

BootstrapVue, with over 40 plugins and more than 80 custom components, custom directives, and over 300 icons, provides one of the most comprehensive implementations of Bootstrap v4 components and grid system for Vue.js. With extensive and automated WAI-AR

import looseEqual from '../../../utils/loose-equal'
import { isArray, isFunction, isPromise } from '../../../utils/inspect'
import { clone } from '../../../utils/object'
import { warn } from '../../../utils/warn'
import listenOnRootMixin from '../../../mixins/listen-on-root'

export default {
  mixins: [listenOnRootMixin],
  props: {
    // Prop override(s)
    items: {
      // Adds in 'Function' support
      type: [Array, Function],
      default() /* istanbul ignore next */ {
        return []
      }
    },
    // Additional props
    noProviderPaging: {
      type: Boolean,
      default: false
    },
    noProviderSorting: {
      type: Boolean,
      default: false
    },
    noProviderFiltering: {
      type: Boolean,
      default: false
    },
    apiUrl: {
      // Passthrough prop. Passed to the context object. Not used by b-table directly
      type: String,
      default: ''
    }
  },
  computed: {
    hasProvider() {
      return isFunction(this.items)
    },
    providerTriggerContext() {
      // Used to trigger the provider function via a watcher. Only the fields that
      // are needed for triggering a provider update are included. Note that the
      // regular this.context is sent to the provider during fetches though, as they
      // may need all the prop info.
      const ctx = {
        apiUrl: this.apiUrl,
        filter: null,
        sortBy: null,
        sortDesc: null,
        perPage: null,
        currentPage: null
      }
      if (!this.noProviderFiltering) {
        // Either a string, or could be an object or array.
        ctx.filter = this.localFilter
      }
      if (!this.noProviderSorting) {
        ctx.sortBy = this.localSortBy
        ctx.sortDesc = this.localSortDesc
      }
      if (!this.noProviderPaging) {
        ctx.perPage = this.perPage
        ctx.currentPage = this.currentPage
      }
      return clone(ctx)
    }
  },
  watch: {
    // Provider update triggering
    items(newVal, oldVal) {
      // If a new provider has been specified, trigger an update
      if (this.hasProvider || isFunction(newVal)) {
        this.$nextTick(this._providerUpdate)
      }
    },
    providerTriggerContext(newVal, oldVal) {
      // Trigger the provider to update as the relevant context values have changed.
      if (!looseEqual(newVal, oldVal)) {
        this.$nextTick(this._providerUpdate)
      }
    }
  },
  mounted() {
    // Call the items provider if necessary
    if (this.hasProvider && (!this.localItems || this.localItems.length === 0)) {
      // Fetch on mount if localItems is empty
      this._providerUpdate()
    }
    // Listen for global messages to tell us to force refresh the table
    this.listenOnRoot('bv::refresh::table', id => {
      if (id === this.id || id === this) {
        this.refresh()
      }
    })
  },
  methods: {
    refresh() {
      // Public Method: Force a refresh of the provider function
      this.$off('refreshed', this.refresh)
      if (this.computedBusy) {
        // Can't force an update when forced busy by user (busy prop === true)
        if (this.localBusy && this.hasProvider) {
          // But if provider running (localBusy), re-schedule refresh once `refreshed` emitted
          this.$on('refreshed', this.refresh)
        }
      } else {
        this.clearSelected()
        if (this.hasProvider) {
          this.$nextTick(this._providerUpdate)
        } else {
          /* istanbul ignore next */
          this.localItems = isArray(this.items) ? this.items.slice() : []
        }
      }
    },
    // Provider related methods
    _providerSetLocal(items) {
      this.localItems = isArray(items) ? items.slice() : []
      this.localBusy = false
      this.$emit('refreshed')
      // New root emit
      if (this.id) {
        this.emitOnRoot('bv::table::refreshed', this.id)
      }
    },
    _providerUpdate() {
      // Refresh the provider function items.
      if (!this.hasProvider) {
        // Do nothing if no provider
        return
      }
      // If table is busy, wait until refreshed before calling again
      if (this.computedBusy) {
        // Schedule a new refresh once `refreshed` is emitted
        this.$nextTick(this.refresh)
        return
      }

      // Set internal busy state
      this.localBusy = true

      // Call provider function with context and optional callback after DOM is fully updated
      this.$nextTick(() => {
        try {
          // Call provider function passing it the context and optional callback
          const data = this.items(this.context, this._providerSetLocal)
          if (isPromise(data)) {
            // Provider returned Promise
            data.then(items => {
              // Provider resolved with items
              this._providerSetLocal(items)
            })
          } else if (isArray(data)) {
            // Provider returned Array data
            this._providerSetLocal(data)
          } else {
            /* istanbul ignore if */
            if (this.items.length !== 2) {
              // Check number of arguments provider function requested
              // Provider not using callback (didn't request second argument), so we clear
              // busy state as most likely there was an error in the provider function
              /* istanbul ignore next */
              warn(
                "Provider function didn't request callback and did not return a promise or data.",
                'BTable'
              )
              this.localBusy = false
            }
          }
        } catch (e) /* istanbul ignore next */ {
          // Provider function borked on us, so we spew out a warning
          // and clear the busy state
          warn(`Provider function error [${e.name}] ${e.message}.`, 'BTable')
          this.localBusy = false
          this.$off('refreshed', this.refresh)
        }
      })
    }
  }
}