https://github.com/easywebapp/iterable-observer

Observable Proposal implement based on Async Generator (ES 2018) & TypeScript
https://github.com/easywebapp/iterable-observer

async generator iterator observable observer proposal

Last synced: 9 days ago
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Observable Proposal implement based on Async Generator (ES 2018) & TypeScript

• Host: GitHub
• URL: https://github.com/easywebapp/iterable-observer
• Owner: EasyWebApp
• Created: 2018-07-30T21:56:20.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2024-08-16T17:53:00.000Z (3 months ago)
• Last Synced: 2024-10-30T00:45:00.732Z (17 days ago)
• Topics: async, generator, iterator, observable, observer, proposal
• Language: TypeScript
• Homepage: https://web-cell.dev/iterable-observer/
• Size: 458 KB
• Stars: 6
• Watchers: 2
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: ReadMe.md
  • Funding: .github/FUNDING.yml

Awesome Lists containing this project

README

        
# Iterable Observer

[Observable Proposal][1] implement based on [Async Generator (ES 2018)][2] & [TypeScript][3]

[![NPM Dependency](https://img.shields.io/librariesio/github/EasyWebApp/iterable-observer.svg)][4]

[![CI & CD](https://github.com/EasyWebApp/iterable-observer/actions/workflows/main.yml/badge.svg)][5]

[![](https://data.jsdelivr.com/v1/package/npm/iterable-observer/badge?style=rounded)][6]

[![NPM](https://nodei.co/npm/iterable-observer.png?downloads=true&downloadRank=true&stars=true)][7]

## Usage

### Basic

```javascript

import { Observable } from 'iterable-observer';

var count = 0,

    list = [];

const observable = new Observable(({ next, complete }) => {

    const timer = setInterval(

        () => (++count < 5 ? next(count) : complete(count)),

        0

    );

    return () => clearInterval(timer);

});

(async () => {

    for await (const item of observable) list.push(item);

    console.log(list); // [1, 2, 3, 4, 5]

})();

```

### Enhance Run-time platforms

#### Transform events

```javascript

import { Observable } from 'iterable-observer';

const reader = new FileReader(),

    { files } = document.querySelector('input[type="file"]');

reader.readAsBlob(files[0]);

(async () => {

    for await (const { loaded } of Observable.fromEvent(reader, 'progress'))

        console.log((loaded / file.size) * 100 + '%');

})();

```

#### Transform streams

```typescript

import { Observable } from 'iterable-observer';

(async () => {

    const { body } = await fetch('https://example.com/path/to/blob'),

        chunks: Uint8Array[] = [];

    for await (const chunk of Observable.fromStream(body)) chunks.push(chunk);

    const blob = new Blob(chunks);

    console.log(blob);

}();

```

### Concurrent Task to Serial Queue

```javascript

import { createQueue } from 'iterable-observer';

import Koa from 'koa';

import BodyParser from 'koa-bodyparser';

const { process, observable } = createQueue(),

    app = new Koa();

(async () => {

    for await (const { defer, data } of observable)

        defer.resolve(JSON.stringify(data));

})();

app.use(BodyParser)

    .use(async context => (context.body = await process(context.request.body)))

    .listen(80);

```

[1]: https://github.com/tc39/proposal-observable

[2]: https://tc39.es/ecma262/#sec-asyncgeneratorfunction-objects

[3]: https://www.typescriptlang.org/

[4]: https://libraries.io/npm/iterable-observer

[5]: https://github.com/EasyWebApp/iterable-observer/actions/workflows/main.yml

[6]: https://www.jsdelivr.com/package/npm/iterable-observer

[7]: https://nodei.co/npm/iterable-observer/