https://github.com/remcoder/computron

Computron is for creating reactive computations, just like ReactiveVar is for reactive values
https://github.com/remcoder/computron

Last synced: 8 months ago
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Computron is for creating reactive computations, just like ReactiveVar is for reactive values

• Host: GitHub
• URL: https://github.com/remcoder/computron
• Owner: remcoder
• License: mit
• Created: 2015-05-08T22:22:57.000Z (almost 11 years ago)
• Default Branch: master
• Last Pushed: 2019-05-27T07:31:56.000Z (almost 7 years ago)
• Last Synced: 2024-04-11T08:53:29.399Z (almost 2 years ago)
• Language: JavaScript
• Homepage:
• Size: 9.77 KB
• Stars: 8
• Watchers: 3
• Forks: 2
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

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README

          
# Computron [![Build Status](https://travis-ci.org/remcoder/computron.svg?branch=master)](https://travis-ci.org/remcoder/computron)

![image](https://user-images.githubusercontent.com/461650/58403119-31abbe00-8062-11e9-8cb7-80b498bf97cc.png)

Computron is for creating reactive _computations_, just like ReactiveVar is for reactive _values_ and was inspired by computed values from [Knockout](http://knockoutjs.com/documentation/computedObservables.html) and [Vue.js](http://vuejs.org/api/options.html#computed).

### Example

    var r1 = new ReactiveVar(21);

    var r2 = new ReactiveVar(21);

    var sum = new Computron(function () {

      return r1.get() + r2.get();

    });

## Installation

	$ meteor add remcoder:computron

## Rationale

While Meteor offers a very flexible way of doing reactivity, having to wrap code in an autorun doesn't always lead to

code that makes the intent clear. This becomes most apparent when you have a cascade of reactive vars that each depend

on one of the other, mixed with side-effects.

TODO: some good examples

## Demo

See in in action [here](http://meteorpad.com/pad/aExzaQ48FAT89Bwba/Computron)

## API

### Creation

    var comp = new Computron()

`computation` : _a function that returns a value. It can make use of reactive sources like Session, ReactiveVar etc._ 

### Example

	var taxRate = 0.2;

	var priceAfterTax = new Computron(function(){

		return Session.get('price') * (1 + taxRate);

	});

To get the current value of the computation, call the `get()` method it. For instance:

     Session.set('priceLabel', 'total :' + priceAfterTax.get() )

The computed value will be updated reactively and propagated to the dependents of the Computron.

### Advanced

The underlying `Tracker.Computation` is accessible from within the callback. Using that you could for instance `stop()` the computation.

	var priceAfterTax = new Computron(function(comp) {

		if (sometging) 

			comp.stop();

		return Session.get('price') * (1 + taxRate);

	});