ofetch

A better fetch API. Works on node, browser, and workers.

Spoiler

Install:

# npm
npm i ofetch

# yarn
yarn add ofetch

Import:

// ESM / Typescript
import { ofetch } from "ofetch";

// CommonJS
const { ofetch } = require("ofetch");

We use conditional exports to detect Node.js and automatically use unjs/node-fetch-native. If globalThis.fetch is available, will be used instead. To leverage Node.js 17.5.0 experimental native fetch API use --experimental-fetch flag.

ofetch will smartly parse JSON and native values using destr, falling back to the text if it fails to parse.

const { users } = await ofetch("/api/users");

For binary content types, ofetch will instead return a Blob object.

You can optionally provide a different parser than destr, or specify blob, arrayBuffer, or text to force parsing the body with the respective FetchResponse method.

// Use JSON.parse
await ofetch("/movie?lang=en", { parseResponse: JSON.parse });

// Return text as is
await ofetch("/movie?lang=en", { parseResponse: (txt) => txt });

// Get the blob version of the response
await ofetch("/api/generate-image", { responseType: "blob" });

If an object or a class with a .toJSON() method is passed to the body option, ofetch automatically stringifies it.

ofetch utilizes JSON.stringify() to convert the passed object. Classes without a .toJSON() method have to be converted into a string value in advance before being passed to the body option.

For PUT, PATCH, and POST request methods, when a string or object body is set, ofetch adds the default content-type: "application/json" and accept: "application/json" headers (which you can always override).

Additionally, ofetch supports binary responses with Buffer, ReadableStream, Stream, and compatible body types. ofetch will automatically set the duplex: "half" option for streaming support!

Example:

const { users } = await ofetch("/api/users", {
  method: "POST",
  body: { some: "json" },
});

ofetch Automatically throws errors when response.ok is false with a friendly error message and compact stack (hiding internals).

A parsed error body is available with error.data. You may also use FetchError type.

await ofetch("https://google.com/404");
// FetchError: [GET] "https://google/404": 404 Not Found
//     at async main (/project/playground.ts:4:3)

To catch error response:

await ofetch("/url").catch((error) => error.data);

To bypass status error catching you can set ignoreResponseError option:

await ofetch("/url", { ignoreResponseError: true });

ofetch Automatically retries the request if an error happens and if the response status code is included in retryStatusCodes list:

Retry status codes:

• 408 - Request Timeout
• 409 - Conflict
• 425 - Too Early (Experimental)
• 429 - Too Many Requests
• 500 - Internal Server Error
• 502 - Bad Gateway
• 503 - Service Unavailable
• 504 - Gateway Timeout

You can specify the amount of retry and delay between them using retry and retryDelay options and also pass a custom array of codes using retryStatusCodes option.

The default for retry is 1 retry, except for POST, PUT, PATCH, and DELETE methods where ofetch does not retry by default to avoid introducing side effects. If you set a custom value for retry it will always retry for all requests.

The default for retryDelay is 0 ms.

await ofetch("http://google.com/404", {
  retry: 3,
  retryDelay: 500, // ms
});

You can specify timeout in milliseconds to automatically abort a request after a timeout (default is disabled).

await ofetch("http://google.com/404", {
  timeout: 3000, // Timeout after 3 seconds
});

The response can be type assisted:

const article = await ofetch<Article>(`/api/article/${id}`);
// Auto complete working with article.id

By using baseURL option, ofetch prepends it for trailing/leading slashes and query search params for baseURL using ufo:

await ofetch("/config", { baseURL });

By using query option (or params as alias), ofetch adds query search params to the URL by preserving the query in the request itself using ufo:

await ofetch("/movie?lang=en", { query: { id: 123 } });

Providing async interceptors to hook into lifecycle events of ofetch call is possible.

You might want to use ofetch.create to set shared interceptors.

onRequest is called as soon as ofetch is called, allowing you to modify options or do simple logging.

await ofetch("/api", {
  async onRequest({ request, options }) {
    // Log request
    console.log("[fetch request]", request, options);

    // Add `?t=1640125211170` to query search params
    options.query = options.query || {};
    options.query.t = new Date();
  },
});

onRequestError will be called when the fetch request fails.

await ofetch("/api", {
  async onRequestError({ request, options, error }) {
    // Log error
    console.log("[fetch request error]", request, error);
  },
});

onResponse will be called after fetch call and parsing body.

await ofetch("/api", {
  async onResponse({ request, response, options }) {
    // Log response
    console.log("[fetch response]", request, response.status, response.body);
  },
});

onResponseError is the same as onResponse but will be called when fetch happens but response.ok is not true.

await ofetch("/api", {
  async onResponseError({ request, response, options }) {
    // Log error
    console.log(
      "[fetch response error]",
      request,
      response.status,
      response.body
    );
  },
});

If necessary, it's also possible to pass an array of function that will be called sequentially.

await ofetch("/api", {
  onRequest: [
    () => {
      /* Do something */
    },
    () => {
      /* Do something else */
    },
  ],
});

This utility is useful if you need to use common options across several fetch calls.

Note: Defaults will be cloned at one level and inherited. Be careful about nested options like headers.

const apiFetch = ofetch.create({ baseURL: "/api" });

apiFetch("/test"); // Same as ofetch('/test', { baseURL: '/api' })

By using headers option, ofetch adds extra headers in addition to the request default headers:

await ofetch("/movies", {
  headers: {
    Accept: "application/json",
    "Cache-Control": "no-cache",
  },
});

If you need to access raw response (for headers, etc), can use ofetch.raw:

const response = await ofetch.raw("/sushi");

// response._data
// response.headers
// ...

As a shortcut, you can use ofetch.native that provides native fetch API

const json = await ofetch.native("/sushi").then((r) => r.json());

In Node.js (>= 18) environments, you can provide a custom dispatcher to intercept requests and support features such as Proxy and self-signed certificates. This feature is enabled by undici built-in Node.js. read more about the Dispatcher API.

Some available agents:

• ProxyAgent: A Proxy Agent class that implements the Agent API. It allows the connection through a proxy in a simple way. (docs)
• MockAgent: A mocked Agent class that implements the Agent API. It allows one to intercept HTTP requests made through undici and return mocked responses instead. (docs)
• Agent: Agent allows dispatching requests against multiple different origins. (docs)

Example: Set a proxy agent for one request:

import { ProxyAgent } from "undici";
import { ofetch } from "ofetch";

const proxyAgent = new ProxyAgent("http://localhost:3128");
const data = await ofetch("https://icanhazip.com", { dispatcher: proxyAgent });

Example: Create a custom fetch instance that has proxy enabled:

import { ProxyAgent, setGlobalDispatcher } from "undici";
import { ofetch } from "ofetch";

const proxyAgent = new ProxyAgent("http://localhost:3128");
const fetchWithProxy = ofetch.create({ dispatcher: proxyAgent });

const data = await fetchWithProxy("https://icanhazip.com");

Example: Set a proxy agent for all requests:

import { ProxyAgent, setGlobalDispatcher } from "undici";
import { ofetch } from "ofetch";

const proxyAgent = new ProxyAgent("http://localhost:3128");
setGlobalDispatcher(proxyAgent);

const data = await ofetch("https://icanhazip.com");

Example: Allow self-signed certificates (USE AT YOUR OWN RISK!)

import { Agent } from "undici";
import { ofetch } from "ofetch";

// Note: This makes fetch unsecure against MITM attacks. USE AT YOUW OWN RISK!
const unsecureAgent = new Agent({ connect: { rejectUnauthorized: false } });
const unsecureFetch = ofetch.create({ dispatcher: unsecureAgent });

const data = await unsecureFetch("https://www.squid-cache.org/");

On older Node.js version (<18), you might also use use agent:

import { HttpsProxyAgent } from "https-proxy-agent";

await ofetch("/api", {
  agent: new HttpsProxyAgent("http://example.com"),
});

By setting the FETCH_KEEP_ALIVE environment variable to true, an HTTP/HTTPS agent will be registered that keeps sockets around even when there are no outstanding requests, so they can be used for future requests without having to re-establish a TCP connection.

Note: This option can potentially introduce memory leaks. Please check node-fetch/node-fetch#1325.

• All targets are exported with Module and CommonJS format and named exports
• No export is transpiled for the sake of modern syntax
  • You probably need to transpile ofetch, destr, and ufo packages with Babel for ES5 support
• You need to polyfill fetch global for supporting legacy browsers like using unfetch

Why export is called ofetch instead of fetch?

Using the same name of fetch can be confusing since API is different but still, it is a fetch so using the closest possible alternative. You can, however, import { fetch } from ofetch which is auto-polyfill for Node.js and using native otherwise.

Why not have default export?

Default exports are always risky to be mixed with CommonJS exports.

This also guarantees we can introduce more utils without breaking the package and also encourage using ofetch name.

Why not transpiled?

By transpiling libraries, we push the web backward with legacy code which is unneeded for most of the users.

If you need to support legacy users, you can optionally transpile the library in your build pipeline.

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