```javascript
// JSONP封装
let count = 1
export default function originPJSONP(option){
// 1.从传入的option中提取URL
const url = option.url;
// 2.在body中添加script标签
const body = document.getElementsByTagName('body')[0]
const script = document.createElement('script');
// 3.内部产生一个不重复的callback
const callback = 'jsonp' + count++
// 4.监听window上的jsonp的调用
return new Promise((resolve, reject) => {
try {
window[callback] = function (result) {
body.removeChild(script);
resolve(result)
}
const params = handleParam(option.data);
script.src = url + '?callback=' + callback + params;
body.appendChild(script)
} catch (e) {
body.removeChild(script)
reject(e)
}
})
}
function handleParam(data) {
let url = '';
for (let key in data) {
let value = data[key] !== undefined ? data[key] : '';
url += `&${key}=${encodeURLComponent(value)}`
}
return url
}
```
