tui-code-snippet/domEvent/off.js

TOAST UI Utility: CodeSnippet

/**
 * @fileoverview Unbind DOM events
 * @author NHN FE Development Lab <dl_javascript@nhn.com>
 */

'use strict';

var isString = require('../type/isString');
var forEach = require('../collection/forEach');

var safeEvent = require('./_safeEvent');

/**
 * Unbind DOM events
 * If a handler function is not passed, remove all events of that type.
 * @param {HTMLElement} element - element to unbind events
 * @param {(string|object)} types - Space splitted events names or eventName:handler object
 * @param {function} [handler] - handler function
 * @memberof module:domEvent
 * @example
 * // Following the example of domEvent#on
 * 
 * // Unbind one event from an element.
 * off(div, 'click', toggle);
 * 
 * // Unbind multiple events with a same handler from multiple elements at once.
 * // Use event names splitted by a space.
 * off(element, 'mouseenter mouseleave', changeColor);
 * 
 * // Unbind multiple events with different handlers from an element at once.
 * // Use an object which of key is an event name and value is a handler function.
 * off(div, {
 *   keydown: highlight,
 *   keyup: dehighlight
 * });
 * 
 * // Unbind events without handlers.
 * off(div, 'drag');
 */
function off(element, types, handler) {
  if (isString(types)) {
    forEach(types.split(/\s+/g), function(type) {
      unbindEvent(element, type, handler);
    });

    return;
  }

  forEach(types, function(func, type) {
    unbindEvent(element, type, func);
  });
}

/**
 * Unbind DOM events
 * If a handler function is not passed, remove all events of that type.
 * @param {HTMLElement} element - element to unbind events
 * @param {string} type - events name
 * @param {function} [handler] - handler function
 * @private
 */
function unbindEvent(element, type, handler) {
  var events = safeEvent(element, type);
  var index;

  if (!handler) {
    forEach(events, function(item) {
      removeHandler(element, type, item.wrappedHandler);
    });
    events.splice(0, events.length);
  } else {
    forEach(events, function(item, idx) {
      if (handler === item.handler) {
        removeHandler(element, type, item.wrappedHandler);
        index = idx;

        return false;
      }

      return true;
    });
    events.splice(index, 1);
  }
}

/**
 * Remove an event handler
 * @param {HTMLElement} element - An element to remove an event
 * @param {string} type - event type
 * @param {function} handler - event handler
 * @private
 */
function removeHandler(element, type, handler) {
  if ('removeEventListener' in element) {
    element.removeEventListener(type, handler);
  } else if ('detachEvent' in element) {
    element.detachEvent('on' + type, handler);
  }
}

module.exports = off;