dom-size-monitor/src/sensorPool.js

监听元素大小变化

import id from './id'
import { createSensor } from './sensors'
import { SizeSensorId } from './constant'

const Sensors = {}

export const getSensor = element => {
  const sensorId = element.getAttribute(SizeSensorId)

  // 1. 已经存在，则直接取这个 sensor
  if (sensorId && Sensors[sensorId]) {
    return Sensors[sensorId]
  }

  // 2. 不存在则创建
  const newId = id()
  element.setAttribute(SizeSensorId, newId)

  const sensor = createSensor(element)
  // 添加到池子中
  Sensors[newId] = sensor

  return sensor
}

export const removeSensor = sensor => {
  const sensorId = sensor.element.getAttribute(SizeSensorId)

  // 移除 attribute
  sensor.element.removeAttribute(SizeSensorId)
  // 移除 sensor 对应的 事件 和 dom 结构
  sensor.destroy()

  // 存在则从 pool 中移除
  if (sensorId && Sensors[sensorId]) {
    delete Sensors[sensorId]
  }
}