bootstrap-vue/src/components/navbar/navbar-toggle.js

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

import Vue from '../../utils/vue'
import listenOnRootMixin from '../../mixins/listen-on-root'
import normalizeSlotMixin from '../../mixins/normalize-slot'
import { getComponentConfig } from '../../utils/config'

const NAME = 'BNavbarToggle'

// TODO: Switch to using VBToggle directive, will reduce code footprint

// Events we emit on $root
const EVENT_TOGGLE = 'bv::toggle::collapse'

// Events we listen to on $root
const EVENT_STATE = 'bv::collapse::state'
// This private event is NOT to be documented as people should not be using it.
const EVENT_STATE_SYNC = 'bv::collapse::sync::state'

// @vue/component
export const BNavbarToggle = /*#__PURE__*/ Vue.extend({
  name: NAME,
  mixins: [listenOnRootMixin, normalizeSlotMixin],
  props: {
    label: {
      type: String,
      default: () => getComponentConfig(NAME, 'label')
    },
    target: {
      type: String,
      required: true
    }
  },
  data() {
    return {
      toggleState: false
    }
  },
  created() {
    this.listenOnRoot(EVENT_STATE, this.handleStateEvt)
    this.listenOnRoot(EVENT_STATE_SYNC, this.handleStateEvt)
  },
  methods: {
    onClick(evt) {
      this.$emit('click', evt)
      if (!evt.defaultPrevented) {
        this.$root.$emit(EVENT_TOGGLE, this.target)
      }
    },
    handleStateEvt(id, state) {
      if (id === this.target) {
        this.toggleState = state
      }
    }
  },
  render(h) {
    return h(
      'button',
      {
        class: ['navbar-toggler'],
        attrs: {
          type: 'button',
          'aria-label': this.label,
          'aria-controls': this.target,
          'aria-expanded': this.toggleState ? 'true' : 'false'
        },
        on: { click: this.onClick }
      },
      [this.normalizeSlot('default') || h('span', { class: ['navbar-toggler-icon'] })]
    )
  }
})