Koa 401错误捕获

当返回http码为401时，Koa将自动去掉allow origin，致使返回的错误变成origin not allowed，这种时候前端没法捕获到这个错误。javascript

解决方法：前端

使用koa-cors，设置options，修改抛出错误的方式。java

// 使用koa-cors
// 注意设置 keepHeadersOnError: true
​
import cors from '@koa/cors'
​
app.use(cors({
        origin: (ctx) => {
            let origin = ctx.request.headers.origin || '';
            const allowedOrigins = ['https://example.site', 'file://'];
            if (allowedOrigins.includes(origin) || origin.includes('localhost')) {
                return origin
            } else {
                return null
            }
​
        },
        allowHeaders: 'Authorization, Origin, No-Cache, X-Requested-With, If-Modified-Since, Pragma, Last-Modified, Cache-Control, Expires, Content-Type, X-E4M-With',
        credentials: true,
        keepHeadersOnError: true
    }))
​
​
//抛出错误让前端捕获
ctx.throw(401,{ code: -2, message: '身份验证失败！'});