Node 跨域 Access to XMLHttpRequest at 'url' from origin 'null' has been blocked by CORS policy: Req...

如果跨域用到了put,patch方法，要在响应头设置

// koa
app.use(async (ctx, next) => {
    ctx.set('Access-Control-Allow-Origin','*')
    ctx.set("Access-Control-Allow-Methods", "POST, GET, DELETE,PATCH,PUT"); 
    ctx.response.status = 200 ;
    await next();
});