jsonp通过Promise的简单实现

jsonp('http://photo.sina.cn/aj/index', {
  page: 1,
  cate: 'recommend'
}, 'jsoncallback').then(res => {
  console.log(res.data);
}).catch(err=>{
  console.log(err);
})

function jsonp(url,data,callback){
  return new Promise((resolve)=>{
    var script = document.createElement('script')
    url += `?jsoncallback=${callback}`
    if(data){
      Object.keys(data).forEach(key=>{
        url += `&${key}=${data[key]}`
      })
    }
    script.src = url
    document.head.appendChild(script)
    window[callback] = function (data){
      resolve(data)
    }
    script.parentNode.removeChild(script)
  })
}

jsonp('http://photo.sina.cn/aj/index', {
  page: 1,
  cate: 'recommend',
}, 'jsoncallback').then(res => {
  console.log(res.data);
}).catch(err=>{
  console.log(err);
})

function jsonp(url,data,callbackName){
 data.callback = callbackName?callbackName : 'callback';
  let paramArr = []
  for(let key in data){
    paramArr.push(`${key}=${data[key]}`);
  }
  let script = document.createElement('script')
  let body = document.getElementsByTagName('body')[0]
  script.src = url + '?' + paramArr.join('&')
  body.appendChild(script)
  return new Promise((resolve,rejiect)=>{
    window[callbackName] = (data)=>{
      resolve(data)
      document.body.removeChild(script)
    }
  })
  
}