Fetch Prime

fetch but with super-powers

• 🔗 Interceptors
• 🔐 Fully typed errors
• 🔌 Platform adapters

Install

npm install fetch-prime fp-ts

<script src="https://unpkg.com/fetch-prime/dist/index.js"></script>

Example

import * as E from "fp-ts/Either";
import { fetch } from "fetch-prime/Fetch";
import adapter from "fetch-prime/Adapters/Platform";

const request = await fetch("/users")(adapter);
const {response} = request;

if (E.isRight(response) && response.right.ok) {
  const users = await response.right.json();
}

// or
import { andThen } from "fetch-prime/Function";
import {filterStatusOk} from "fetch-prime/Response";

const request = await fetch("/users")(adapter);
const ok = andThen(request.response, filterStatusOk);
const users = await andThen(ok, (res) => res.json());

// or
const response = await fetch("/users")(adapter);
const users = await response.ok((res) => res.json());

With interceptor

import * as Interceptor from "fetch-prime/Interceptor";
import BaseURL from "fetch-prime/Interceptors/Url";

const baseURL = "https://reqres.in/api";

// our list of interceptors
const interceptors = Interceptor.of(BaseURL(baseURL));
// or
const interceptors = Interceptor.add(Interceptor.empty(), BaseURL(baseURL));

// make function that executes our interceptors
const interceptor = Interceptor.make(interceptors);

// we finally make the HTTP adapter
const intercept_adapter = interceptor(adapter);

const response = await fetch("/users")(intercept_adapter);

Adapters

fetch-prime provides a default adapter that uses the platform fetch.

import FetchAdapter from "fetch-prime/Adapters/Platform";

You can write your own adapter i.e using XMLHttpRequest

Interceptors

fetch-prime ships with the following interceptors

• Base URL
• Timeout
• Logger
• Status Filter
• Bearer and Basic authentication

Example

Instead of checking if the response is ok i.e 200

const response = await fetch("/users")(adapter);
const users = await response.ok(res => res.json());

We can delegate that to a response interceptor that performs that check.

const interceptors = Interceptor.of(StatusOK);

const interceptor = Interceptor.make(interceptors);

const adapter = interceptor(Adapter);

const response = await fetch("/users")(adapter);
const users = await response.json();
// ...

Writing your own interceptor

import * as Interceptor from "fetch-prime/Interceptor";

const my_interceptor = async function (chain: Interceptor.Chain) {
  const clone = chain.request.clone(); // do something with request
  const response = await chain.proceed(chain.request);
  // do something with response
  return response;
};

Interceptors are executed in the order which they were added (top to bottom).

more examples