# ![Popsicle](logo.svg)
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> Advanced HTTP requests in node.js and browsers, using [Servie](https://github.com/serviejs/servie).
## Installation
```
npm install popsicle --save
```
## Usage
```js
import { fetch } from "popsicle";
const res = await fetch("http://example.com");
const data = await res.text();
```
> Popsicle is a universal package, meaning node.js and browsers are supported without any configuration. This means the primary endpoint requires some `dom` types in TypeScript. When in a node.js or browser only environments prefer importing `popsicle/dist/{node,browser}` instead.
Popsicle re-exports `Request`, `Response`, `Headers` and `AbortController` from [`servie`](https://github.com/serviejs/servie). The `fetch` function accepts the same arguments as [`Request`](https://github.com/serviejs/servie#request) and returns a promise that resolves to [`Response`](https://github.com/serviejs/servie#response). You can use the [`Signal`](https://github.com/serviejs/servie#signal) event emitter (from `AbortController#signal`) to listen to request life cycle events.
### [Browser](./src/browser.ts)
The middleware stack for browsers contains _only_ the `XMLHttpRequest` transport layer, browsers handle all other request normalization. This means a smaller and faster package for browsers.
### [Node.js](./src/node.ts)
The middleware stack for node.js includes normalization to act similar to browsers:
- Default `User-Agent`
- Support for decoding compressed payloads
- Follows HTTP redirects
- Caches cookies in-memory
> **Important:** If you are doing anything non-trivial with Popsicle, please override the `User-Agent` and respect `robots.txt`.
### Recipes
#### Aborting a Request
```ts
import { fetch, AbortController } from "popsicle";
const controller = new AbortController();
setTimeout(() => controller.abort(), 500);
const res = fetch("http://example.com", {
signal: controller.signal
});
```
### Errors
Transports can return an error. The built-in codes are documented below:
- **EUNAVAILABLE** Unable to connect to the remote URL
- **EINVALID** Request URL is invalid (browsers)
- **EMAXREDIRECTS** Maximum number of redirects exceeded (node.js)
- **EBLOCKED** The request was blocked (HTTPS -> HTTP) (browsers)
- **ECSP** Request violates the documents Content Security Policy (browsers)
- **ETYPE** Invalid transport type (browsers)
### Customization
Build the functionality you require by composing middleware functions and using `toFetch`. See [`src/node.ts`](./src/node.ts) for an example.
## Plugins
- [Popsicle Status](https://github.com/serviejs/popsicle-status) - Reject on invalid HTTP status codes
- [Popsicle Retry](https://github.com/serviejs/popsicle-retry) - Retry HTTP requests on bad server responses
### Creating Plugins
See [Throwback](https://github.com/serviejs/throwback#usage) for more information:
```ts
type Plugin = (
req: Request,
next: () => Promise<Response>
) => Promise<Response>;
```
## TypeScript
This project is written using [TypeScript](https://github.com/Microsoft/TypeScript) and publishes the types to NPM alongside the package.
## Related Projects
- [Superagent](https://github.com/visionmedia/superagent) - HTTP requests for node and browsers
- [Fetch](https://github.com/github/fetch) - Browser polyfill for promise-based HTTP requests
- [Axios](https://github.com/mzabriskie/axios) - HTTP request API based on Angular's `$http` service
## License
MIT