Support interceptors

[mzabriskie]

See Angular's spec for reference https://docs.angularjs.org/api/ng/service/$http#interceptors

[kentcdodds]

Can I help with this? I'm using js-data and I need this working for my authentication to work :-)

[jmdobry]

👍

[mzabriskie]

Here's a couple approaches for the API that might work:

// 1) This style follows Angular's $http service
axios.interceptors.push({
  request: function (config) {},
  requestError: function (rejection) {},
  response: function (response) {},
  responseError: function (rejection) {}
});

// 2) This style follows express middleware
axios.interceptors.request.use(function (config) {}, function (rejection) {});
axios.interceptors.response.use(function (config) {}, function (rejection) {});

The first option has the benefit of familiarity for those coming from Angular. That said it is not enough to mimic an API based on familiarity, especially if it's not a good API. As @jmdobry mentioned offline, "pushing stuff into some random array [is] kinda dumb". I agree that arbitrarily pushing some config object onto an array is less than ideal.

The second option allows for simplicity by just passing in a function, and axios knowing if the function is to be used for request, or response. It is a little uglier to only specify a requestError handler for example, since you have to provide a null value for the request handler:

axios.interceptors.request.use(null, function (rejection) {});

A third option could be to do a hybrid of the two. Expose an API that supports the second option, but under the hood it just creates what option one is doing. This would allow for both options to be supported.

[mzabriskie]

Closed with #27