element-plus/packages/hooks/use-escape-keydown/index.ts

import { onBeforeUnmount, onMounted } from 'vue'
import { getEventCode, isClient } from '@element-plus/utils'
import { EVENT_CODE } from '@element-plus/constants'

let registeredEscapeHandlers: ((e: KeyboardEvent) => void)[] = []

const cachedHandler = (event: KeyboardEvent) => {
  const code = getEventCode(event)
  if (code === EVENT_CODE.esc) {
    registeredEscapeHandlers.forEach((registeredHandler) =>
      registeredHandler(event)
    )
  }
}

export const useEscapeKeydown = (handler: (e: KeyboardEvent) => void) => {
  onMounted(() => {
    if (registeredEscapeHandlers.length === 0) {
      document.addEventListener('keydown', cachedHandler)
    }
    if (isClient) registeredEscapeHandlers.push(handler)
  })

  onBeforeUnmount(() => {
    registeredEscapeHandlers = registeredEscapeHandlers.filter(
      (registeredHandler) => registeredHandler !== handler
    )
    if (registeredEscapeHandlers.length === 0) {
      if (isClient) document.removeEventListener('keydown', cachedHandler)
    }
  })
}