eventsMixin() — vue Function Reference

Architecture documentation for the eventsMixin() function in events.ts from the vue codebase.

Function typescript VueCore Instance

Entity Profile

VueCore→ Instance→ eventsMixin() — vue Function Reference

Dependency Diagram

graph TD
  8c55e9cc_003e_88f5_29af_162432bc1494["eventsMixin()"]
  8c1ef0ac_57c2_7f8a_7ea7_6924e38bf16b["events.ts"]
  8c55e9cc_003e_88f5_29af_162432bc1494 -->|defined in| 8c1ef0ac_57c2_7f8a_7ea7_6924e38bf16b
  style 8c55e9cc_003e_88f5_29af_162432bc1494 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

src/core/instance/events.ts lines 59–160

export function eventsMixin(Vue: typeof Component) {
  const hookRE = /^hook:/
  Vue.prototype.$on = function (
    event: string | Array<string>,
    fn: Function
  ): Component {
    const vm: Component = this
    if (isArray(event)) {
      for (let i = 0, l = event.length; i < l; i++) {
        vm.$on(event[i], fn)
      }
    } else {
      ;(vm._events[event] || (vm._events[event] = [])).push(fn)
      // optimize hook:event cost by using a boolean flag marked at registration
      // instead of a hash lookup
      if (hookRE.test(event)) {
        vm._hasHookEvent = true
      }
    }
    return vm
  }

  Vue.prototype.$once = function (event: string, fn: Function): Component {
    const vm: Component = this
    function on() {
      vm.$off(event, on)
      fn.apply(vm, arguments)
    }
    on.fn = fn
    vm.$on(event, on)
    return vm
  }

  Vue.prototype.$off = function (
    event?: string | Array<string>,
    fn?: Function
  ): Component {
    const vm: Component = this
    // all
    if (!arguments.length) {
      vm._events = Object.create(null)
      return vm
    }
    // array of events
    if (isArray(event)) {
      for (let i = 0, l = event.length; i < l; i++) {
        vm.$off(event[i], fn)
      }
      return vm
    }
    // specific event
    const cbs = vm._events[event!]
    if (!cbs) {
      return vm
    }
    if (!fn) {
      vm._events[event!] = null
      return vm
    }
    // specific handler
    let cb
    let i = cbs.length
    while (i--) {
      cb = cbs[i]
      if (cb === fn || cb.fn === fn) {
        cbs.splice(i, 1)
        break
      }
    }
    return vm
  }

  Vue.prototype.$emit = function (event: string): Component {
    const vm: Component = this
    if (__DEV__) {
      const lowerCaseEvent = event.toLowerCase()
      if (lowerCaseEvent !== event && vm._events[lowerCaseEvent]) {
        tip(
          `Event "${lowerCaseEvent}" is emitted in component ` +
            `${formatComponentName(
              vm