axios添加了header信息后发送的get请求自动编程option请求了

webpack 代理转发

Provisional headers are shown

在Vue中如何使用axios跨域访问数据

如果你是跨域请求，服务端返回响应时需要添加headers: Access-Control-Allow-Origin: *

express:

    // Website you wish to allow to connect

    res.setHeader('Access-Control-Allow-Origin', '*');

    // Request methods you wish to allow

    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, PATCH, DELETE');

    // Request headers you wish to allow

    res.setHeader('Access-Control-Allow-Headers', 'X-Requested-With,content-type');

    // Set to true if you need the website to include cookies in the requests sent

    // to the API (e.g. in case you use sessions)

    res.setHeader('Access-Control-Allow-Credentials', true);