element-plus/packages/utils/dom/event.ts

export const composeEventHandlers = <E>(
  theirsHandler?: (event: E) => boolean | void,
  oursHandler?: (event: E) => void,
  { checkForDefaultPrevented = true } = {}
) => {
  const handleEvent = (event: E) => {
    const shouldPrevent = theirsHandler?.(event)

    if (checkForDefaultPrevented === false || !shouldPrevent) {
      return oursHandler?.(event)
    }
  }
  return handleEvent
}

type WhenMouseHandler = (e: PointerEvent) => any
export const whenMouse = (handler: WhenMouseHandler): WhenMouseHandler => {
  return (e: PointerEvent) =>
    e.pointerType === 'mouse' ? handler(e) : undefined
}