Sagu

Simple Async Generator Utils

Game changer of javascript asynchronous process.
Sagu convert async callback functions to simple loop.

Sagu how change async process of javascript?

Stream api

So far

const res = await fetch('http://ex.com/stream');
res.body.pipeTo(new WritableStream({
  write(chunk) {
    console.log("Chunk received", chunk);
  },
  close() {
    console.log("All data successfully read!");
  },
  abort(e) {
    console.error("Something went wrong!", e);
  }
}));

With sagu

for await (const {chunk, ok, done} of stream('http://ex.com/stream', {binary: true})) {
  console.log(chunk.read());
}

Event

So far

const a = document.querySelector('a');
a.addEventListener('click', e => console.log(e.target.nodeName));

With sagu

const a = document.querySelector('a');
for await (const {event, dispose} of event(a, 'click')) {
  console.log(event.target.nodeName);
}

Socket.IO

So far

const conn = io('http://www.sample.com/ws');
conn.on('connection', ...);
conn.on('request', ...);

With sagu

for await (const {type, event} of ws('http://www.sample.com/ws', ws)) {
  switch (type) {
    case 'connection':
    ...
    case 'request':
    ...
  }
  ...
}

Polling

So far

// polling.
async function poll() {
  const res = await fetch('https://sample.com');
  const json = res.json();
  ...
  setTimeout(poll, 1000);
};
poll();

With sagu

// polling
for await (const {ok, response} of poll('https://sample.com', {}, 1000)) {
  const json = await response.json();
  ...
}

etc...

Sagu convert async callback function to simple loops.

Install

npm install sagu --save

Import

ES6

import {
  wait,
  ws
} from 'sagu';

Node

const {
  wait,
  ws 
} = require('sagu');

Script

<script src="<path to sagu>/sagu/dist/index-iife.js"></script> 
<script>console.log(sagu.wait)</script> 

For rollup users

Use rollup-plugin-node-resolve with module: true.

For Webpack or other bundler users

Import normaly.

Environment

Sagu only works for environment which support asynchronous iterater(for-await-of).
Now only babel support that feature.
So now we support only babel transpilation.

babel config.

"babel": {
  "plugins": [
    [
      "transform-runtime",
      {
        "helpers": false,
        "polyfill": false,
        "regenerator": true,
        "moduleName": "babel-runtime"
      }
    ]
  ],
  "presets": [
    "es2015",
    "stage-3"
  ]
}

You must specify stage-3 presets and transform-runtime.
In detail,see
https://github.com/babel/babel/pull/3473
https://github.com/tc39/proposal-async-iteration

API

See API