text: 
  // 图片异步加载
  function loadImageAsync(url){
      return new Promise( (resolve,reject) => {
          let img = new Image()
          img.src = url
          img.onload = () => {
              resolve(img)
          }
          img.onerror = () => {
              resolve({src: null})
          }
      })
  }
  
  
  export default {
      loadImageAsync
  }
  