Axios拦截器的错误处理程序何时被调用？

Question

I have setup an axios interceptor with the aim of putting a global loading variable to true when any request has not received a response. In my app this will prevent the user from submitting a form which is many cases could cause errors as all data has not yet been processed.

The code is:

var numberOfAjaxCAllPending = 0;
// Add a request interceptor
window.axios.interceptors.request.use(function (config) {
    numberOfAjaxCAllPending++;
    console.log('Request:  ---- ' + numberOfAjaxCAllPending);
    return config;
}, function (error) {
    return Promise.reject(error);
});

// Add a response interceptor
window.axios.interceptors.response.use(function (response) {
    numberOfAjaxCAllPending--;
    console.log('Pending Response (response): ---- ' + numberOfAjaxCAllPending);
    return response;
}, function (error) {
    numberOfAjaxCAllPending--;
    console.log('Pending Response (error): ---- ' + numberOfAjaxCAllPending);
    return Promise.reject(error);
});

global.loading = numberOfAjaxCAllPending > 0;

As a request is made, the pending counter is incremented and as a response comes back in its decremented. A value greater than 0 means requests are still pending.

I am a little confused about the error part of the promise on each of these. I have to add the decrement pending to response error so that it can catch non 200 responses.

With the request, I assume if there is an error then the request will not send and I will not be expecting a response. Is this correct?

Answer 1

On request interceptor, you also need to decrement the value if you dont want to wait for response.

Function in request interceptor will be invoked before it does request.

Function in response interceptor will be invoked after response is received.

That said if error occurs after request interceptor is called, you need to decrement the value. If error occurs before request interceptor, you dont need to decrement it.

It just depends on when the error occurs.