jsonp跨域 封装通用方法
//用法如下
jsonp({
url:"http://localhost:3000/say",
params:{wd:'你好，服务端！'},
callback:'show'
}).then(data=>{
console.log(data);
});
//封装实现
function jsonp({url,params,callback}){//异步执行返回promise
return new Promise((resolve,reject)=>{
//创建script标签
let script = document.createElement('script');
//声明回调
window[callback] = function(data){
resolve(data);
//删除script标签
document.body.removeChild(script);
}
//解构参数
params = {...params,callback}
let arr = [];
//拼接处理
for(let key in params){
arr.push(`${key}=${params[key]}`)
}
script.src = `${url}?${arr.join('&')}`;
//添加到body
document.body.appendChild(script);
})
}
//借鉴 珠峰架构课姜文老师
server.js
//服务端代码
let express = requeire('express');
let app = express();
app.get('/say',function(req,res){
let {wd,callback} = req.query;
res.end(`${callback}('你好！客户端')`)
})
app.listen(3000)
