angularjs http interceptor class (ES6) loses binding to 'this'

Question

I am building and AngularJS app using ES6 classes with traceur transpiling to ES5 in AMD format.

in my module I import the interceptor class and register it as a service

Answer 1

Look at these lines of source code:

// apply interceptors
forEach(reversedInterceptors, function(interceptor) {
    if (interceptor.request || interceptor.requestError) {
        chain.unshift(interceptor.request, interceptor.requestError);
    }
    if (interceptor.response || interceptor.responseError) {
        chain.push(interceptor.response, interceptor.responseError);
    }
});

When interceptor.responseError method is pushed into chain it looses its context (just function is pushed, without any context);

Later here it will be added to promise as reject callback:

while (chain.length) {
    var thenFn = chain.shift();
    var rejectFn = chain.shift();

    promise = promise.then(thenFn, rejectFn);
}

So if promise will be rejected, rejectFn(your responseError function) will be executed as an ordinary function. In this case this references to window if script is being executed in non-strict mode, or equals null otherwise.

IMHO Angular 1 was written with ES5 consideration, so I think using it with ES6 is not a good idea.