react-lazyload/lib/utils/event.js

Lazyload your components, images or anything where performance matters.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.on = on;
exports.off = off;
function on(el, eventName, callback, opts) {
  opts = opts || false;
  if (el.addEventListener) {
    el.addEventListener(eventName, callback, opts);
  } else if (el.attachEvent) {
    el.attachEvent("on" + eventName, function (e) {
      callback.call(el, e || window.event);
    });
  }
}

function off(el, eventName, callback, opts) {
  opts = opts || false;
  if (el.removeEventListener) {
    el.removeEventListener(eventName, callback, opts);
  } else if (el.detachEvent) {
    el.detachEvent("on" + eventName, callback);
  }
}