observable and it's `compute` function (
https://github.com/dominictarr/observable#compute ) can do the same
```js
var o = require('observable')
var first = o()
var last = o()
var fullName = o.compute([first, last], function (f, l) { return f + " " +
l })
fullName(function onChange(fullName) {
/* do stuff */
})
```
@Rick the reason to use an observable abstraction is to listen to change
notifications. i.e. the observable / computable abstraction should be push
based, meaning that when a property changes all computed properties and
their listeners are notified of the change.
You could use `Object.observe` but that requires observing mutable objects
where as `observable` can work in an immutable / read-only / reactive
fashion
On Mon, Mar 11, 2013 at 2:59 PM, Tristan Slominski <
[email protected]> wrote:
> lol... I think you're mostly right. That's what happens if I'm looking at
> it from only one perspective.
>
> I guess a difference is a minor one, and that would be with the ability to
> listen to the "update" event:
>
> full.on('update', function(updatedValue) {
> console.log('update:', updatedValue);
> });
>
> That seems to be outside of the object meta API yes? (although your point
> is well taken, and computed-value doesn't seem like much of an
> improvement over it).
>
> Thanks for pointing it out, I need to think some more about it.
>
>
> On Monday, March 11, 2013 4:00:13 PM UTC-5, Rick Waldron wrote:
>>
>> I haven't seen anything so far that couldn't be done with the object meta
>> API...
>>
>> var fname = "John", lname = "Doe";
>>
>> Object.defineProperty(this, "full", {
>> get: function() {
>> return fname + " " + lname;
>> }
>> });
>>
>> full;
>> // "John Doe"
>>
>>
>> On Monday, March 11, 2013, Tristan Slominski wrote:
>>
>>> Thanks Andrey, those are great pointers, I'll take a look.
>>>
>>> On Monday, March 11, 2013 2:08:09 PM UTC-5, Андрей Листочкин wrote:
>>>>
>>>> Another similar project:
>>>> http://component.io/**w**eepy/attr<http://component.io/weepy/attr>
>>>>
>>>> It's a component, not the npm package but it's pretty easy to add it to
>>>> your project since it's only one file.
>>>>
>>>> The API is similar to Knockout js http://knockoutjs.com/**docum**
>>>> entation/**computedObservables.**html<http://knockoutjs.com/documentation/computedObservables.html>
>>>>
>>>> var firstName = attr('John'), lastName = attr('Dow'), fullName =
>>>> attr(function () {
>>>> return firstName() + ' ' + lastName()
>>>> })
>>>>
>>>> lastName('Resig')
>>>>
>>>> fullName() // === 'John Resig'
>>>>
>>>> It does the same thing as your package but does automatic dependency
>>>> resolution and tracking. Take a look!
>>>>
>>>> BTW that's one of the reasons why I prefer something like Knockout or
>>>> Angular to Ember.
>>>>
>>>> Andrey
>>>>
>>>> On Mar 11, 2013, at 02:22 , Tristan Slominski wrote:
>>>>
>>>> I saw a presentation, recently, on Ember.js computed properties. This
>>>> got me curious about reactive programming.
>>>>
>>>> computed-value is a tiny library that allows developers to very simply
>>>> specify dependencies between properties and recalculate them every time one
>>>> of those dependent properties changes. This isn't a new idea, but I've
>>>> attempted to make it as small and as powerful as possible. (And in the
>>>> spirit of "stream all the things", I attempted to use the new "streams2"
>>>> under the hood, so it requires node >= 0.9.12).
>>>>
>>>> If you're interested in reactive programming I would love some feedback
>>>> on the API. It's still brand new, and experimental.
>>>>
>>>> Here's a computed full name example:
>>>>
>>>> var cv = require('computed-value');
>>>>
>>>> var first = cv('John');
>>>> var last = cv('Smith');
>>>> var full = cv(first, last, function(first, last) {
>>>> return first + ' ' + last;
>>>> });
>>>>
>>>> console.log(full.value);
>>>>
>>>> first.write('Bob');
>>>> console.log(full.value);
>>>>
>>>> full.on('update', function(updatedValue) {
>>>> console.log('update:', updatedValue);
>>>> });
>>>>
>>>> last.write('Johnson');
>>>>
>>>> You can find the project here: https://github.com/**trist**
>>>> anls/node-computed-value<https://github.com/tristanls/node-computed-value>
>>>>
>>>> Cheers,
>>>>
>>>> Tristan
>>>>
>>>> --
>>>> --
>>>> Job Board: http://jobs.nodejs.org/
>>>> Posting guidelines: https://github.com/joyent/**node**
>>>> /wiki/Mailing-List-**Posting-**Guidelines<https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines>
>>>> You received this message because you are subscribed to the Google
>>>> Groups "nodejs" group.
>>>> To post to this group, send email to [email protected]
>>>> To unsubscribe from this group, send email to
>>>> nodejs+un...@**googlegroups.com
>>>> For more options, visit this group at
>>>> http://groups.google.com/**group**/nodejs?hl=en?hl=en<http://groups.google.com/group/nodejs?hl=en?hl=en>
>>>>
>>>> ---
>>>> You received this message because you are subscribed to the Google
>>>> Groups "nodejs" group.
>>>> To unsubscribe from this group and stop receiving emails from it, send
>>>> an email to nodejs+un...@**googlegroups.com.
>>>> For more options, visit
>>>> https://groups.google.com/**grou**ps/opt_out<https://groups.google.com/groups/opt_out>
>>>> .
>>>>
>>>>
>>>>
>>>>
>>>> --
>>> --
>>> Job Board: http://jobs.nodejs.org/
>>> Posting guidelines: https://github.com/joyent/**node/wiki/Mailing-List-*
>>> *Posting-Guidelines<https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines>
>>> You received this message because you are subscribed to the Google
>>> Groups "nodejs" group.
>>> To post to this group, send email to [email protected]
>>> To unsubscribe from this group, send email to
>>> nodejs+unsubscribe@**googlegroups.com
>>> For more options, visit this group at
>>> http://groups.google.com/**group/nodejs?hl=en?hl=en<http://groups.google.com/group/nodejs?hl=en?hl=en>
>>>
>>> ---
>>> You received this message because you are subscribed to the Google
>>> Groups "nodejs" group.
>>> To unsubscribe from this group and stop receiving emails from it, send
>>> an email to nodejs+unsubscribe@**googlegroups.com.
>>> For more options, visit
>>> https://groups.google.com/**groups/opt_out<https://groups.google.com/groups/opt_out>
>>> .
>>>
>>>
>>>
>> --
> --
> Job Board: http://jobs.nodejs.org/
> Posting guidelines:
> https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines
> You received this message because you are subscribed to the Google
> Groups "nodejs" group.
> To post to this group, send email to [email protected]
> To unsubscribe from this group, send email to
> [email protected]
> For more options, visit this group at
> http://groups.google.com/group/nodejs?hl=en?hl=en
>
> ---
> You received this message because you are subscribed to the Google Groups
> "nodejs" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to [email protected].
> For more options, visit https://groups.google.com/groups/opt_out.
>
>
>
--
--
Job Board: http://jobs.nodejs.org/
Posting guidelines:
https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines
You received this message because you are subscribed to the Google
Groups "nodejs" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to
[email protected]
For more options, visit this group at
http://groups.google.com/group/nodejs?hl=en?hl=en
---
You received this message because you are subscribed to the Google Groups
"nodejs" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/groups/opt_out.
