on-resize.js

/*
 * Copyright 2014-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import ResizeObserver from 'resize-observer-polyfill';

const observers = new WeakMap();

const bind = (el, binding) => {
  unbind(el);
  const observer = new ResizeObserver(binding.value);
  observer.observe(el);
  observers.set(el, observer);

};

const unbind = (el) => {
  const observer = observers.get(el);
  if (observer) {
    observer.disconnect();
    observers.delete(el);
  }
};

export default {
  bind,
  update(el, binding) {
    if (binding.value === binding.oldValue) {
      return
    }
    bind(el, binding)
  },
  unbind
}