查漏补缺——说说Promise.reject

问题

如题所示

答案

相关源码：

service.interceptors.request.use(
    config => {
        // do something before request is sent

        // if (store.getters.token) {
        //     config.headers['X-Token'] = getToken()
        // }
        return config
    },
    error => {
        // do something with request error
        console.log(error) // for debug
        return Promise.reject(error)
    }
)

// response interceptor
service.interceptors.response.use(
    /**
     * If you want to get http information such as headers or status
     * Please return  response => response
     */

    /**
     * Determine the request status by custom code
     * Here is just an example
     * You can also judge the status by HTTP Status Code
     */
    response => {
        const res = response.data
        // store.commit('SET_LOADING',false);

        // if the custom code is not 20000, it is judged as an error.
        if (res.code !== 20000) {
            return Promise.reject(new Error(res.message || 'Error'))
        } else {
            return res
        }
    },
    error => {
        console.log('err' + error) // for debug
        return Promise.reject(error)
    }
)

Promise初步详解（resolve，reject，catch）

综上所述，这个Promise对象的reject方法会将Promise对象的状态转换为rejected，也就是意味着操作失败，然后把错误传进来。