TypeScript

axios ships TypeScript definitions in the npm package via index.d.ts (ESM) and index.d.cts (CJS), so type checking and editor support work out of the box for both module formats.

Module resolution caveats

Because axios dual-publishes with an ESM default export and a CJS module.exports, there are a few configuration caveats:

• The recommended setting is "moduleResolution": "node16" (implied by "module": "node16"). This requires TypeScript 4.7 or greater.
• If you use ESM, your settings should be fine.
• If you compile TypeScript to CJS and you can't use "moduleResolution": "node16", you must enable esModuleInterop.
• If you use TypeScript to type-check CJS JavaScript code, your only option is "moduleResolution": "node16".

Type guards for axios errors

Use the axios.isAxiosError type guard to safely narrow unknown errors in catch blocks. After narrowing, you can access axios-specific properties like error.response, error.config, and error.code with full type safety.

import axios from "axios";

let user: User | null = null;
try {
  const { data } = await axios.get("/user?ID=12345");
  user = data.userDetails;
} catch (error) {
  if (axios.isAxiosError(error)) {
    handleAxiosError(error);
  } else {
    handleUnexpectedError(error);
  }
}

Use axios.isCancel<T>() to narrow cancellation errors to CanceledError<T>:

const controller = new AbortController();

try {
  await axios.get<User>("/user?ID=12345", { signal: controller.signal });
} catch (error) {
  if (axios.isCancel<User>(error)) {
    handleCancellation(error);
  }
}

Typed instances and interceptors

Annotate the result of axios.create with AxiosInstance, and annotate request interceptors with InternalAxiosRequestConfig to get end-to-end type checking on a custom client:

import axios, { AxiosInstance, InternalAxiosRequestConfig } from "axios";

const apiClient: AxiosInstance = axios.create({
  baseURL: "https://api.example.com",
  timeout: 10000,
});

apiClient.interceptors.request.use((config: InternalAxiosRequestConfig) => {
  // Add auth token, log, etc.
  return config;
});

Typing response data

Axios request methods are generic over the response data type. Pass a type parameter to axios.get<T> (and the other aliases) to type response.data:

interface User {
  id: number;
  name: string;
}

const { data } = await apiClient.get<User>("/users/1");
// `data` is typed as `User`