dom-helpers/cjs/addEventListener.js

tiny modular DOM lib for ie9+

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

exports.__esModule = true;
exports.default = exports.onceSupported = exports.optionsSupported = void 0;

var _canUseDOM = _interopRequireDefault(require("./canUseDOM"));

/* eslint-disable no-return-assign */
var optionsSupported = false;
exports.optionsSupported = optionsSupported;
var onceSupported = false;
exports.onceSupported = onceSupported;

try {
  var options = {
    get passive() {
      return exports.optionsSupported = optionsSupported = true;
    },

    get once() {
      // eslint-disable-next-line no-multi-assign
      return exports.onceSupported = onceSupported = exports.optionsSupported = optionsSupported = true;
    }

  };

  if (_canUseDOM.default) {
    window.addEventListener('test', options, options);
    window.removeEventListener('test', options, true);
  }
} catch (e) {
  /* */
}

/**
 * An `addEventListener` ponyfill, supports the `once` option
 */
function addEventListener(node, eventName, handler, options) {
  if (options && typeof options !== 'boolean' && !onceSupported) {
    var once = options.once,
        capture = options.capture;
    var wrappedHandler = handler;

    if (!onceSupported && once) {
      wrappedHandler = handler.__once || function onceHandler(event) {
        this.removeEventListener(eventName, onceHandler, capture);
        handler.call(this, event);
      };

      handler.__once = wrappedHandler;
    }

    node.addEventListener(eventName, wrappedHandler, optionsSupported ? options : capture);
  }

  node.addEventListener(eventName, handler, options);
}

var _default = addEventListener;
exports.default = _default;