CODEWITHSUNDEEP
typescript
Xen_mar
Xen_mar

Reputation: 9672

Augment default export in TypeScript?

Some packages export only a single object. If I were to overwrite/extend that object: How would I do that?

After searching a lot of answers this is where I am:

import axios from "axios";

declare module "axios" {
  const axios: {
    not: () => void;
  };

  export = axios; // <- Exports and export assignments are not permitted in module augmentations.
}

axios.not();

This question is not about whether it is practical to overwrite axios here

Upvotes: 3

Views: 765

Answers (1)

Guerric P
Guerric P

Reputation: 31805

TypeScript has declaration merging abilities, unfortunately, in your case you won't be able to leverage it because of its limitations:

Disallowed Merges Not all merges are allowed in TypeScript. Currently, classes can not merge with other classes or with variables. For information on mimicking class merging, see the Mixins in TypeScript section.

As the documentation says, on the other hand you can leverage mixins to create your own class that extends Axios:

import { Axios } from "axios";

type AxiosConstructor = new (...args: any[]) => Axios;

function augmentAxios<T extends AxiosConstructor>(axios: T) {
    return class AugmentedAxios extends axios {
        newAbility() {}
    };
}

const AugmentedAxios = augmentAxios(Axios);

const augmentedAxios = new AugmentedAxios({});

augmentedAxios.post('http://test'); // Base ability
augmentedAxios.newAbility(); // New ability

Upvotes: 1

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