test

IdleUnload.js

((async () => {
  const sleep = ms => new Promise(r => setTimeout(r, ms))
  class IdleUnload {
      /**
       * @param obj Unloadable 对象
       * @param idleTime 超时时间 单位为秒
       */
      constructor(obj, idleTime) {
          this.obj = obj;
          this.loaded = false;
          this.task = Promise.resolve();
          this.running = 0;
          this.idleTime = idleTime * 1000;
      }
      async execute(...args) {
          if (this.timeoutId !== undefined) {
              window.clearTimeout(this.timeoutId);
          }
          await this.doLoad();
          try {
              this.running++;
              return await this.obj.execute(...args);
          }
          finally {
              this.running--;
              this.afterRun();
          }
      }
      getFunc() {
          return (...args) => this.execute(...args);
      }
      afterRun() {
          if (this.running === 0) {
              if (this.timeoutId !== undefined) {
                  window.clearTimeout(this.timeoutId);
              }
              this.timeoutId = window.setTimeout(() => this.doUnload(), this.idleTime);
          }
      }
      async doLoad() {
          await this.append(async () => {
              if (this.loaded === false) {
                  await this.obj.load();
                  this.loaded = true;
              }
          });
      }
      async doUnload() {
          await this.append(async () => {
              if (this.loaded === true) {
                  await this.obj.unload();
                  this.loaded = false;
              }
          });
      }
      async append(fac) {
          this.task = this.task.then(fac);
          await this.task;
      }
  }
  function idleUnload(obj, idleTime) {
      return (new IdleUnload(obj, idleTime)).getFunc();
  }
  
  let times = 0
  const f = idleUnload({
	  async load () {
		  console.log('loading')
		  await sleep(1000)
		  this.loaded = true
		  console.log('load done')
	  },
	  async unload () {
		  console.log('unloading')
		  await sleep(1000)
		  this.loaded = false
		  console.log('unload done')
	  },
	  async execute () {
		  const id = ++times
		  console.log('executing', this.loaded, id)
		  await sleep(500)
		  console.log('execute done', this.loaded, id)
	  }
  }, 1)
  
  await f()
  await f()
  await sleep(2000)
  f()
  await sleep(200)
  f()
  await sleep(200)
  f()
  await sleep(200)
  f()
  await sleep(200)
  f()
  await sleep(200)
  f()
  await sleep(200)
  f()
  await sleep(200)
  f()
  await sleep(200)
  f()
  await sleep(200)
  f()
  await sleep(200)
  f()
})(), undefined)