diff --git a/README.md b/README.md
index c4d1a22..738805a 100644
--- a/README.md
+++ b/README.md
@@ -1,15 +1,46 @@
-
node-fetch
==========
-[![npm stable version][npm-image]][npm-url]
-[![npm next version][npm-next-image]][npm-url]
+[![npm version][npm-image]][npm-url]
[![build status][travis-image]][travis-url]
[![coverage status][codecov-image]][codecov-url]
[![install size][install-size-image]][install-size-url]
A light-weight module that brings `window.fetch` to Node.js
+
+
+- [Motivation](#motivation)
+- [Features](#features)
+- [Difference from client-side fetch](#difference-from-client-side-fetch)
+- [Installation](#installation)
+- [Loading and configuring the module](#loading-and-configuring-the-module)
+- [Common Usage](#common-usage)
+ - [Plain text or HTML](#plain-text-or-html)
+ - [JSON](#json)
+ - [Simple Post](#simple-post)
+ - [Post with JSON](#post-with-json)
+ - [Post with form parameters](#post-with-form-parameters)
+ - [Handling exceptions](#handling-exceptions)
+ - [Handling client and server errors](#handling-client-and-server-errors)
+- [Advanced Usage](#advanced-usage)
+ - [Streams](#streams)
+ - [Buffer](#buffer)
+ - [Accessing Headers and other Meta data](#accessing-headers-and-other-meta-data)
+ - [Post data using a file stream](#post-data-using-a-file-stream)
+ - [Post with form-data (detect multipart)](#post-with-form-data-detect-multipart)
+- [API](#api)
+ - [fetch(url[, options])](#fetchurl-options)
+ - [Options](#options)
+ - [Class: Request](#class-request)
+ - [Class: Response](#class-response)
+ - [Class: Headers](#class-headers)
+ - [Interface: Body](#interface-body)
+ - [Class: FetchError](#class-fetcherror)
+- [License](#license)
+- [Acknowledgement](#acknowledgement)
+
+
## Motivation
@@ -17,171 +48,204 @@ Instead of implementing `XMLHttpRequest` in Node.js to run browser-specific [Fet
See Matt Andrews' [isomorphic-fetch](https://github.com/matthew-andrews/isomorphic-fetch) or Leonardo Quixada's [cross-fetch](https://github.com/lquixada/cross-fetch) for isomorphic usage (exports `node-fetch` for server-side, `whatwg-fetch` for client-side).
-
## Features
- Stay consistent with `window.fetch` API.
-- Make conscious trade-off when following [whatwg fetch spec][whatwg-fetch] and [stream spec](https://streams.spec.whatwg.org/) implementation details, document known difference.
+- Make conscious trade-off when following [WHATWG fetch spec][whatwg-fetch] and [stream spec](https://streams.spec.whatwg.org/) implementation details, document known differences.
- Use native promise, but allow substituting it with [insert your favorite promise library].
-- Use native stream for body, on both request and response.
-- Decode content encoding (gzip/deflate) properly, convert `res.text()` output to UTF-8 optionally.
-- Useful extensions such as timeout, redirect limit, response size limit, [explicit errors][ERROR-HANDLING.md] for troubleshooting.
-
+- Use native Node streams for body, on both request and response.
+- Decode content encoding (gzip/deflate) properly, and convert string output (such as `res.text()` and `res.json()`) to UTF-8 automatically.
+- Useful extensions such as timeout, redirect limit, response size limit, [explicit errors](ERROR-HANDLING.md) for troubleshooting.
## Difference from client-side fetch
-- See [Known Differences][LIMITS.md] for details.
+- See [Known Differences](LIMITS.md) for details.
- If you happen to use a missing feature that `window.fetch` offers, feel free to open an issue.
- Pull requests are welcomed too!
+## Installation
-## Install
-
-Stable release (`2.x`)
+Current stable release (`2.x`)
```sh
$ npm install node-fetch --save
```
-## Usage
+## Loading and configuring the module
+We suggest you load the module via `require`, pending the stabalizing of es modules in node:
+```js
+const fetch = require('node-fetch');
+```
-Note that documentation below is up-to-date with `2.x` releases, [see `1.x` readme](https://github.com/bitinn/node-fetch/blob/1.x/README.md), [changelog](https://github.com/bitinn/node-fetch/blob/1.x/CHANGELOG.md) and [2.x upgrade guide][UPGRADE-GUIDE.md] if you want to find out the difference.
+If you are using a Promise library other than native, set it through fetch.Promise:
+```js
+const Bluebird = require('bluebird');
-```javascript
-import fetch from 'node-fetch';
-// or
-// const fetch = require('node-fetch');
+fetch.Promise = Bluebird;
+```
-// if you are using your own Promise library, set it through fetch.Promise. Eg.
+## Common Usage
-// import Bluebird from 'bluebird';
-// fetch.Promise = Bluebird;
-
-// plain text or html
+NOTE: The documentation below is up-to-date with `2.x` releases, [see `1.x` readme](https://github.com/bitinn/node-fetch/blob/1.x/README.md), [changelog](https://github.com/bitinn/node-fetch/blob/1.x/CHANGELOG.md) and [2.x upgrade guide](UPGRADE-GUIDE.md) for the differences.
+#### Plain text or HTML
+```js
fetch('https://github.com/')
- .then(res => res.text())
- .then(body => console.log(body));
+ .then(res => res.text())
+ .then(body => console.log(body));
+```
-// json
+#### JSON
+
+```js
fetch('https://api.github.com/users/github')
- .then(res => res.json())
- .then(json => console.log(json));
+ .then(res => res.json())
+ .then(json => console.log(json));
+```
-// catching network error
-// 3xx-5xx responses are NOT network errors, and should be handled in then()
-// you only need one catch() at the end of your promise chain
+#### Simple Post
+```js
+fetch('https://httpbin.org/post', { method: 'POST', body: 'a=1' })
+ .then(res => res.json()) // expecting a json response
+ .then(json => console.log(json));
+```
-fetch('http://domain.invalid/')
- .catch(err => console.error(err));
+#### Post with JSON
-// stream
-// the node.js way is to use stream when possible
+```js
+const body = { a: 1 };
-fetch('https://assets-cdn.github.com/images/modules/logos_page/Octocat.png')
- .then(res => {
- return new Promise((resolve, reject) => {
- const dest = fs.createWriteStream('./octocat.png');
- res.body.pipe(dest);
- res.body.on('error', err => {
- reject(err);
- });
- dest.on('finish', () => {
- resolve();
- });
- dest.on('error', err => {
- reject(err);
- });
- });
- });
+fetch('https://httpbin.org/post', {
+ method: 'post',
+ body: JSON.stringify(body),
+ headers: { 'Content-Type': 'application/json' },
+ })
+ .then(res => res.json())
+ .then(json => console.log(json));
+```
-// buffer
-// if you prefer to cache binary data in full, use buffer()
-// note that buffer() is a node-fetch only API
+#### Post with form parameters
+`URLSearchParams` is available in Node.js as of v7.5.0. See [official documentation](https://nodejs.org/api/url.html#url_class_urlsearchparams) for more usage methods.
-import fileType from 'file-type';
+NOTE: The `Content-Type` header is only set automatically to `x-www-form-urlencoded` when an instance of `URLSearchParams` is given as such:
-fetch('https://assets-cdn.github.com/images/modules/logos_page/Octocat.png')
- .then(res => res.buffer())
- .then(buffer => fileType(buffer))
- .then(type => { /* ... */ });
-
-// meta
-
-fetch('https://github.com/')
- .then(res => {
- console.log(res.ok);
- console.log(res.status);
- console.log(res.statusText);
- console.log(res.headers.raw());
- console.log(res.headers.get('content-type'));
- });
-
-// post
-
-fetch('http://httpbin.org/post', { method: 'POST', body: 'a=1' })
- .then(res => res.json())
- .then(json => console.log(json));
-
-// post with stream from file
-
-import { createReadStream } from 'fs';
-
-const stream = createReadStream('input.txt');
-fetch('http://httpbin.org/post', { method: 'POST', body: stream })
- .then(res => res.json())
- .then(json => console.log(json));
-
-// post with JSON
-
-var body = { a: 1 };
-fetch('http://httpbin.org/post', {
- method: 'POST',
- body: JSON.stringify(body),
- headers: { 'Content-Type': 'application/json' },
-})
- .then(res => res.json())
- .then(json => console.log(json));
-
-// post form parameters (x-www-form-urlencoded)
-
-import { URLSearchParams } from 'url';
+```js
+const { URLSearchParams } = require('url');
const params = new URLSearchParams();
params.append('a', 1);
-fetch('http://httpbin.org/post', { method: 'POST', body: params })
- .then(res => res.json())
- .then(json => console.log(json));
-// post with form-data (detect multipart)
+fetch('https://httpbin.org/post', { method: 'POST', body: params })
+ .then(res => res.json())
+ .then(json => console.log(json));
+```
-import FormData from 'form-data';
+#### Handling exceptions
+NOTE: 3xx-5xx responses are *NOT* exceptions, and should be handled in `then()`, see the next section.
+
+Adding a catch to the fetch promise chain will catch *all* exceptions, such as errors originating from node core libraries, like network errors, and operational errors which are instances of FetchError. See the [error handling document](ERROR-HANDLING.md) for more details.
+
+```js
+fetch('https://domain.invalid/')
+ .catch(err => console.error(err));
+```
+
+#### Handling client and server errors
+It is common to create a helper function to check that the response contains no client (4xx) or server (5xx) error responses:
+
+```js
+function checkStatus(res) {
+ if (res.ok) { // res.status >= 200 && res.status < 300
+ return res;
+ } else {
+ throw MyCustomError(res.statusText);
+ }
+}
+
+fetch('https://httpbin.org/status/400')
+ .then(checkStatus)
+ .then(res => console.log('will not get here...'))
+```
+
+## Advanced Usage
+
+#### Streams
+The "Node.js way" is to use streams when possible:
+
+```js
+fetch('https://assets-cdn.github.com/images/modules/logos_page/Octocat.png')
+ .then(res => {
+ const dest = fs.createWriteStream('./octocat.png');
+ res.body.pipe(dest);
+ });
+```
+
+[TODO]: # (Somewhere i think we also should mention arrayBuffer also if you want to be cross-fetch compatible.)
+
+#### Buffer
+If you prefer to cache binary data in full, use buffer(). (NOTE: buffer() is a `node-fetch` only API)
+
+```js
+const fileType = require('file-type');
+
+fetch('https://assets-cdn.github.com/images/modules/logos_page/Octocat.png')
+ .then(res => res.buffer())
+ .then(buffer => fileType(buffer))
+ .then(type => { /* ... */ });
+```
+
+#### Accessing Headers and other Meta data
+```js
+fetch('https://github.com/')
+ .then(res => {
+ console.log(res.ok);
+ console.log(res.status);
+ console.log(res.statusText);
+ console.log(res.headers.raw());
+ console.log(res.headers.get('content-type'));
+ });
+```
+
+#### Post data using a file stream
+
+```js
+const { createReadStream } = require('fs');
+
+const stream = createReadStream('input.txt');
+
+fetch('https://httpbin.org/post', { method: 'POST', body: stream })
+ .then(res => res.json())
+ .then(json => console.log(json));
+```
+
+#### Post with form-data (detect multipart)
+
+```js
+const FormData = require('form-data');
const form = new FormData();
form.append('a', 1);
-fetch('http://httpbin.org/post', { method: 'POST', body: form })
- .then(res => res.json())
- .then(json => console.log(json));
-// post with form-data (custom headers)
-// note that getHeaders() is non-standard API
+fetch('https://httpbin.org/post', { method: 'POST', body: form })
+ .then(res => res.json())
+ .then(json => console.log(json));
-import FormData from 'form-data';
+// OR, using custom headers
+// NOTE: getHeaders() is non-standard API
const form = new FormData();
form.append('a', 1);
-fetch('http://httpbin.org/post', { method: 'POST', body: form, headers: form.getHeaders() })
- .then(res => res.json())
- .then(json => console.log(json));
-// node 7+ with async function
+const options = {
+ method: 'POST',
+ body: form,
+ headers: form.getHeaders()
+}
-(async function () {
- const res = await fetch('https://api.github.com/users/github');
- const json = await res.json();
- console.log(json);
-})();
+fetch('https://httpbin.org/post', options)
+ .then(res => res.json())
+ .then(json => console.log(json));
```
See [test cases](https://github.com/bitinn/node-fetch/blob/master/test/test.js) for more examples.
@@ -197,27 +261,29 @@ See [test cases](https://github.com/bitinn/node-fetch/blob/master/test/test.js)
Perform an HTTP(S) fetch.
-`url` should be an absolute url, such as `http://example.com/`. A path-relative URL (`/file/under/root`) or protocol-relative URL (`//can-be-http-or-https.com/`) will result in a rejected promise.
+`url` should be an absolute url, such as `https://example.com/`. A path-relative URL (`/file/under/root`) or protocol-relative URL (`//can-be-http-or-https.com/`) will result in a rejected promise.
+
+[TODO]: # (It might be a good idea to reformat the options section into a table layout, like the headers section, instead of current code block.)
-#### Options
+### Options
The default values are shown after each option key.
```js
{
- // These properties are part of the Fetch Standard
- method: 'GET',
- headers: {}, // request headers. format is the identical to that accepted by the Headers constructor (see below)
- body: null, // request body. can be null, a string, a Buffer, a Blob, or a Node.js Readable stream
- redirect: 'follow', // set to `manual` to extract redirect headers, `error` to reject redirect
+ // These properties are part of the Fetch Standard
+ method: 'GET',
+ headers: {}, // request headers. format is the identical to that accepted by the Headers constructor (see below)
+ body: null, // request body. can be null, a string, a Buffer, a Blob, or a Node.js Readable stream
+ redirect: 'follow', // set to `manual` to extract redirect headers, `error` to reject redirect
- // The following properties are node-fetch extensions
- follow: 20, // maximum redirect count. 0 to not follow redirect
- timeout: 0, // req/res timeout in ms, it resets on redirect. 0 to disable (OS limit applies)
- compress: true, // support gzip/deflate content encoding. false to disable
- size: 0, // maximum response body size in bytes. 0 to disable
- agent: null // http(s).Agent instance, allows custom proxy, certificate, lookup, family etc.
+ // The following properties are node-fetch extensions
+ follow: 20, // maximum redirect count. 0 to not follow redirect
+ timeout: 0, // req/res timeout in ms, it resets on redirect. 0 to disable (OS limit applies)
+ compress: true, // support gzip/deflate content encoding. false to disable
+ size: 0, // maximum response body size in bytes. 0 to disable
+ agent: null // http(s).Agent instance, allows custom proxy, certificate etc.
}
```
@@ -225,6 +291,8 @@ The default values are shown after each option key.
If no values are set, the following request headers will be sent automatically:
+[TODO]: # ("we always said content-length will be "automatically calculated, if possible" in the default header section, but we never explain what's the condition for it to be calculated, and that chunked transfer-encoding will be used when they are not calculated or supplied." - "Maybe also add Transfer-Encoding: chunked? That header is added by Node.js automatically if the input is a stream, I believe.")
+
Header | Value
----------------- | --------------------------------------------------------
`Accept-Encoding` | `gzip,deflate` _(when `options.compress === true`)_
@@ -296,6 +364,8 @@ Because Node.js does not implement service workers (for which this class was des
#### response.ok
+*(spec-compliant)*
+
Convenience property representing if the request ended normally. Will evaluate to true if the response status was greater than or equal to 200 but smaller than 300.
@@ -379,6 +449,8 @@ Consume the body and return a promise that will resolve to one of these formats.
Consume the body and return a promise that will resolve to a Buffer.
+[TODO]: # (textConverted API should mention an optional dependency on encoding, which users need to install by themselves, and this is done purely for backward compatibility with 1.x release.)
+
#### body.textConverted()
*(node-fetch extension)*
@@ -394,18 +466,15 @@ Identical to `body.text()`, except instead of always converting to UTF-8, encodi
An operational error in the fetching process. See [ERROR-HANDLING.md][] for more info.
-## License
-
-MIT
-
-
## Acknowledgement
Thanks to [github/fetch](https://github.com/github/fetch) for providing a solid implementation reference.
+## License
+
+MIT
[npm-image]: https://img.shields.io/npm/v/node-fetch.svg?style=flat-square
-[npm-next-image]: https://img.shields.io/npm/v/node-fetch/next.svg?style=flat-square
[npm-url]: https://www.npmjs.com/package/node-fetch
[travis-image]: https://img.shields.io/travis/bitinn/node-fetch.svg?style=flat-square
[travis-url]: https://travis-ci.org/bitinn/node-fetch
@@ -413,11 +482,10 @@ Thanks to [github/fetch](https://github.com/github/fetch) for providing a solid
[codecov-url]: https://codecov.io/gh/bitinn/node-fetch
[install-size-image]: https://packagephobia.now.sh/badge?p=node-fetch
[install-size-url]: https://packagephobia.now.sh/result?p=node-fetch
-
-[ERROR-HANDLING.md]: https://github.com/bitinn/node-fetch/blob/master/ERROR-HANDLING.md
-[LIMITS.md]: https://github.com/bitinn/node-fetch/blob/master/LIMITS.md
-[UPGRADE-GUIDE.md]: https://github.com/bitinn/node-fetch/blob/master/UPGRADE-GUIDE.md
-
[whatwg-fetch]: https://fetch.spec.whatwg.org/
[response-init]: https://fetch.spec.whatwg.org/#responseinit
[node-readable]: https://nodejs.org/api/stream.html#stream_readable_streams
+[mdn-headers]: https://developer.mozilla.org/en-US/docs/Web/API/Headers
+[LIMITS.md]: https://github.com/bitinn/node-fetch/blob/master/LIMITS.md
+[ERROR-HANDLING.md]: https://github.com/bitinn/node-fetch/blob/master/ERROR-HANDLING.md
+[UPGRADE-GUIDE.md]: https://github.com/bitinn/node-fetch/blob/master/UPGRADE-GUIDE.md
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