Add tests for type definitions

[remcohaszing]

Is your feature request related to a problem? Please describe.

Currently there are not automated tests for axios type definitions. This has lead to breakage in the past, and is likely to cause issues in the future. Also the axios team seems to be hesitant to merge type enhancements, because they don’t have a lot of experience with TypeScript themselves (as far as I could tell).

Describe the solution you'd like

I would like to add automated tests using dtslint. This is the same tool to test types that is used by DefinitelyTyped. An example of what this would look like can be found in JedWatson/classnames#251.

Describe alternatives you've considered

N/A

Additional context

The latest (0.22.0) axios types are broken at the moment of writing.

[imransilvake]

I am getting the following typescript error on 0.22.0:

is there a fix for this issue?

before, the header type was:

export interface AxiosRequestConfig {
  headers?: any;
}  

[udebella]

@imransilvake your issue seems to match #4108

[matushorvath]

@imransilvake your issue seems to match #4108

I believe this issue was created as a request to add tests that will prevent similar problems in future, rather than to fix this particular problem. I would second that request, we also found today that our production code that compiles and works with axios 0.21 suddenly contains lots of type errors when compiling against axios 0.22. Adding tests to catch similar issues before a release would be a significant quality improvement for people who use TypeScript.

[remcohaszing]

I’m willing to set this up if an axios member agrees.

[jasonsaayman]

@remcohaszing please go ahead, more testing is almost always welcomed