Axios Tutorial

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Axios Docs

Install

npm install axios

<script src="https://cdn.jsdelivr.net/npm/axios/dist/axios.min.js"></script>

First Request

• import axios

• axios.get(url)

• axios.post(url)

• axios.patch/put(url)

• axios.delete(url)

• default get axios(url)

• returns a promise

• response data located in data property

• error in error.response

import axios from "axios";

const fetchData = async () => {
  try {
    // axios.get(), axios.post(),axios.put(), axios.delete()
    const response = await axios(url);

    console.log(response);
  } catch (error) {
    console.log(error.response);
  }
};

Headers

• second argument

• axios.get(url,{})

• third argument in requests with data

• axios.post(url,{data},{})

const fetchDadJoke = async () => {
  // the url returns html by default so we pass an object `{headers:{Accept: "application/json"}}` to inform the server to provide the response in JSON format.
  try {
    const { data } = await axios(url, {
      headers: {
        Accept: "application/json",
      },
    });
    // console.log(data);
    setJoke(data.joke);
  } catch (error) {
    console.log(error.response);
  }
};

Post Request

• send data to the server
• axios.post(url, { data })
• more options (auth header) - axios.post(url, { data },{})

try {
  const resp = await axios.post(url, { data });
} catch (error) {
  console.log(error.response.data);
}

Global Defaults

// In latest axios version common property returns "undefined"
// axios.defaults.headers.common['Accept'] = 'application/json';
axios.defaults.headers["Accept"] = "application/json";

axios.defaults.baseURL = "https://api.example.com";

// In latest axios version common property returns "undefined"
// axios.defaults.headers.common['Authorization'] = AUTH_TOKEN;
axios.defaults.headers["Authorization"] = AUTH_TOKEN;

axios.defaults.headers.post["Content-Type"] =
  "application/x-www-form-urlencoded";

Custom Instance

const authFetch = axios.create({
  baseURL: "https://www.course-api.com",
  headers: {
    Accept: "application/json",
  },
});

Interceptors

• global and custom

authFetch.interceptors.request.use(
  (request) => {
    // request.headers.common['Accept'] = `application/json`;
    request.headers["Accept"] = `application/json`;

    console.log("request sent");
    // must return request
    return request;
  },
  (error) => {
    return Promise.reject(error);
  },
);

authFetch.interceptors.response.use(
  (response) => {
    console.log("got response");
    return response;
  },
  (error) => {
    console.log(error.response);
    if (error.response.status === 404) {
      // do something
      console.log("NOT FOUND");
    }
    return Promise.reject(error);
  },
);

Update

In the latest version there is no common property

// In latest axios version common property returns "undefined"
// axios.defaults.headers.common['Accept'] = 'application/json';
axios.defaults.headers["Accept"] = "application/json";

// In latest axios version common property returns "undefined"
// axios.defaults.headers.common['Authorization'] = AUTH_TOKEN;
axios.defaults.headers["Authorization"] = AUTH_TOKEN;

// request.headers.common['Accept'] = `application/json`;
request.headers["Accept"] = `application/json`;