Hamsa – A simple data-binding and observable model

Re:Hamsa – A simple data-binding and observable model by netgusto on Sunday March 22, 2015 @05:54AM (#9246198)

IMHO, one-way data flow + immutability competes with (beats ?) observed mutations in many use cases.

See https://youtu.be/I7IdS-PbEgI, and more specifically https://youtu.be/I7IdS-PbEgI?t=21m29s

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Re:Hamsa – A simple data-binding and observable model by wereHamster on Sunday March 22, 2015 @10:46AM (#9246872)

I have a library which builds on top of O.o [1]. I dig immutability but immutable.js is far from perfect, especially when used from within a strongly typed language:

    first.setIn(["foo","val"], 500)

The type checker can not verify that `first.foo.bar` exists and is of type Number!

Avers plays nicely with TypeScript (it's actually written in TS). If I add proper property type annotations to the objects, TypeScript will warn me when I try to access or modify a property which doesn't exist.

It is true that O.o libraries modify the objects in-place. But that's only an issue if you consider those objects the ground source of truth. But there is a different way to look at it: Treat O.o just as a way to observe changes, but then apply them to immutable stores. Something which I may add support for in the future (see [2], "Immutable applyOperation").

Another way to look at it is: When you render the UI with React, you have to pass React the data (stores, objects) as well as a specification how it is allowed to modify the data. Avers sort of combines the two so you only have to pass around one reference which includes both. How you handle the changes (whether by mutating the objects in-place or applying them to immutable stores) is up to you.

[1]: https://github.com/wereHamster/avers [2]: https://caurea.org/2015/02/08/the-future-of-avers.html

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Re:Hamsa – A simple data-binding and observable model by rsuelzer on Sunday March 22, 2015 @12:08PM (#9247230)

As an aside around dealing with properties that don't exist yet, I have found the following pattern very useful. It greatly reduces the number of checks I have to do in an if statement and has made my code more maintainable by reducing the amount of boilerplate code I need to write inside of functions.

http://adripofjavascript.com/blog/drips/making-deep-property...

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Re:Hamsa – A simple data-binding and observable model by wereHamster on Sunday March 22, 2015 @02:22PM (#9247707)

That avoids runtime exceptions, but won't save you from typos.

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Re:Hamsa – A simple data-binding and observable model by sooheon on Sunday March 22, 2015 @10:48AM (#9246879)

I recently read the re-frame ~manifesto~README[1] which is a compelling write up about that concept. Could you share some others initiatives in this vein?

[1]https://github.com/Day8/re-frame

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Re:Hamsa – A simple data-binding and observable model by netgusto on Wednesday March 25, 2015 @04:24AM (#9261763)

Also: https://twitter.com/teozaurus/status/518071391959388160

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Re:Hamsa – A simple data-binding and observable model by dominotw on Sunday March 22, 2015 @10:50AM (#9246890)

Your views are still observing/reacting to changes in stores no?

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