fineui/src/core/element/plugins/event.js

var returnThis = function () {
  return this;
};
export const registEventFun = (Element) => {
  [
    'mousedown',
    'mouseup',
    'mousewheel',
    'keydown',
    'keyup',
    'focus',
    'focusin',
    'focusout',
    'click',
    'on',
    'off',
    'bind',
    'unbind',
    'trigger',
    'hover',
    'scroll',
    'scrollLeft',
    'scrollTop',
    'resize',
    'show',
    'hide',
    'dblclick',
    'blur',
  ].forEach((event) => {
    Element.registerFunction(event, returnThis);
  });
};