Fetch API in Node.js with specific response type

Table of contents

• Pre-requisites
• Setup
  • Install
  • Usage
    • Node.js
    • Native ES modules or TypeScript
• API Reference
  • fetchAs
  • FetchAsData<T>
  • fetchAsArrayBuffer(url[, options])
  • fetchAsBlob(url[, options])
  • fetchAsBuffer(url[, options])
  • fetchAsJson(url[, options])
  • fetchAsText(url[, options])
  • fetchAsTextConverted(url[, options])
• License

Pre-requisites

• Node.js >= 8.9.0
• NPM >= 5.5.1 (NPM comes with Node.js so there is no need to install separately.)

Setup

Install

# Install via NPM
$ npm install --save fetch-as

Usage

Node.js

const { fetchAs } = require('fetch-as');
// OR require each method explicitly
// const {
//   fetchAsArrayBuffer,
//   fetchAsBlob,
//   fetchAsBuffer,
//   fetchAsJson,
//   fetchAsText,
//   fetchAsTextConverted,
// } = require('fetch-as');

async function runFetch() {
  const url = 'http://www.mocky.io/v2/5a50cfa82f000085158d5315';
  const jsonData = await fetchAs.json(url); // OR fetchAsJson(url);

  console.log('# json', jsonData);
  // {
  //   "status": 200,
  //   "message": "OK",
  //   "by": "fetch-as"
  // }
}

runFetch();

Native ES modules or TypeScript

import fetchAs from 'fetch-as';
// OR import each method explicitly
// import {
//   fetchAsArrayBuffer,
//   fetchAsBlob,
//   fetchAsBuffer,
//   fetchAsJson,
//   fetchAsText,
//   fetchAsTextConverted,
// } from 'fetch-as';

async function runFetch() {
  const url = 'http://www.mocky.io/v2/5a50cfa82f000085158d5315';
  const jsonData = await fetchAs.json(url); // OR fetchAsJson(url);

  console.log('# json', jsonData);
  // {
  //   "status": 200,
  //   "message": "OK",
  //   "by": "fetch-as"
  // }
}

runFetch();

API Reference

fetchAs

This contains a collection of methods that will convert the response into the specified data type:

• .arrayBuffer(url[, options]) Method which will return a ArrayBuffer.
• .blob(url[,options]) Method which will return a Blob.
• .buffer(url[, options]) Method which will return a Buffer.
• .json(url[, options]) Method which will return a JSON data which can consumed by JavaScript as Object.
• .text(url[, options]) Method which will return a text/ string.
• .textConverted(url[, options]) Method which will return a text/ string, except instead of always converting to UTF-8, encoding sniffing will be performed and text converted to UTF-8, if possible.

FetchAsData<T>

Response data returned in the type of T where T might be one of the values: Buffer, Object, or string.

• <status> HTTP response status code. Any response that has a HTTP status greater than 399 can be regarded as an error response.
• <data<T>> This contains the successful response data of type T. Only shows when the HTTP response status code is less than 400.
• <error<T>> This contains the error response data of type T. Only shows when the HTTP response status code is greater than 399.

fetchAsArrayBuffer(url[, options])

• url <string> A string representing the URL for fetching.
• options <Object> Options for HTTP(S) request. See Options for a list of supported options.
• returns: <Promise<FetchAsData<ArrayBuffer>> Promise which resolves with a FetchAsData of type ArrayBuffer.

fetchAsBlob(url[, options])

• url <string> A string representing the URL for fetching.
• options <Object> Options for HTTP(S) request. See Options for a list of supported options.
• returns: <Promise<FetchAsData<Blob>> Promise which resolves with a FetchAsData of type Blob.

fetchAsBuffer(url[, options])

• url <string> A string representing the URL for fetching.
• options <Object> Options for HTTP(S) request. See Options for a list of supported options.
• returns: <Promise<FetchAsData<Buffer>> Promise which resolves with a FetchAsData of type Buffer.

fetchAsJson(url[, options])

• url <string> A string representing the URL for fetching.
• options <Object> Options for HTTP(S) request. See Options for a list of supported options.
• returns: <Promise<FetchAsData<Object>> Promise which resolves with a FetchAsData of type JSON which can consumed by JavaScript as Object.

fetchAsText(url[, options])

• url <string> A string representing the URL for fetching.
• options <Object> Options for HTTP(S) request. See Options for a list of supported options.
• returns: <Promise<FetchAsData<string>> Promise which resolves with a FetchAsData of type string.

fetchAsTextConverted(url[, options])

* Please note that encoding is required to be installed in order to use this method.

• Identical to fetchAsText(url[, options]), except instead of always converting to UTF-8, encoding sniffing will be performed and text converted to UTF-8, if possible.

License

MIT License © Rong Sen Ng