maxfierke/ember-procrastination

No code is more concurrent than code that does not run and then runs all at once, suddenly.

ember-procrastination

Did you know that almost no language implements procrastination primitives? Of course, Java offers a ProcrastinationFactory, .NET has System.Enterprise.ProcrastinationServices and Haskell has that powerful Procrastinate monad. However, to date no one has ever implemented anything like this for Ember or JavaScript. Sad.

Overview

ember-procrastination introduces a new concurrency primitive called a someday. A someday is a lot like a task from ember-concurrency, but has the special property that it will only schedule and do work when prompted several times. This means that only work the user truly wants done will get completed. But be careful: if you ask too much, it may get mad and cancel work already in-progress. Such truly concurrent code can be finicky.

ember-procrastination also leverages the best in lazy code loading technology to ensure that we don’t execute expensive operations until the last possible moment. To do this, ember-procrastination uses an advanced Just-In-Time (JIT) feature present in modern JavaScript: the beforeunload event. When ember-procrastination detects this event, all code that has been previously prompted to run that has not yet been run will run, ensuring that all work is completed. And it all happens concurrently. Amazing.

Installation

$ ember install ember-procrastination

Example

controller.js:

import Ember from 'ember';
import { someday } from 'ember-procrastination';
import { timeout } from 'ember-concurrency';

export default Ember.Controller.extend({
  regenerateNumber: someday(function* () {
    this.set('num', Math.random());
    yield timeout(1000);
  })
});

template.hbs

<span>
  Number is: {{num}}
</span>
<pre>
  state = {{regenerateNumber.state}}
  lastExcuse = {{regenerateNumber.lastExcuse}}
</pre>
<br />
<button
  type="button"
  disabled={{regenerateNumber.isRunning}}
  onClick={{procrastinate regenerateNumber}}>
  {{#if (and regenerateNumber.isProcrastinating regenerateNumber.lastExcuse)}}
    {{regenerateNumber.lastExcuse}}
  {{else if regenerateNumber.isRunning}}
    Doing the thing...
  {{else if regenerateNumber.isQueued}}
    Ugh... Why do you keep asking me to do stuff?
  {{else}}
    Do the Thing
  {{/if}}
</button>

Developing

• git clone <repository-url> this repository
• cd ember-procrastination
• npm install

Running

• ember serve
• Visit your app at http://localhost:4200.

Running Tests

• npm test (Runs ember try:each to test your addon against multiple Ember versions)
• ember test
• ember test --server

Building

• ember build

For more information on using ember-cli, visit https://ember-cli.com/.