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https://github.com/derhuerst/data-down-actions-up
Enforce the Data Down, Actions Up™ paradigm.
https://github.com/derhuerst/data-down-actions-up
frontend virtual-dom
Last synced: about 19 hours ago
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Enforce the Data Down, Actions Up™ paradigm.
- Host: GitHub
- URL: https://github.com/derhuerst/data-down-actions-up
- Owner: derhuerst
- License: isc
- Created: 2017-01-24T23:03:52.000Z (about 8 years ago)
- Default Branch: master
- Last Pushed: 2020-06-17T14:14:50.000Z (over 4 years ago)
- Last Synced: 2025-02-08T01:46:22.471Z (13 days ago)
- Topics: frontend, virtual-dom
- Language: JavaScript
- Homepage: https://github.com/derhuerst/data-down-actions-up
- Size: 13.7 KB
- Stars: 3
- Watchers: 2
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: readme.md
- License: license.md
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README
# data-down-actions-up
**Enforce the *Data Down, Actions Up™* paradigm.**
[](https://www.npmjs.com/package/data-down-actions-up)
[](https://travis-ci.org/derhuerst/data-down-actions-up)
[](https://david-dm.org/derhuerst/data-down-actions-up)
[](https://david-dm.org/derhuerst/data-down-actions-up#info=devDependencies)
[](https://gitter.im/derhuerst)
@maxogden, @yoshuawuyts and other people have shaped the notion of **[*Data Down, Actions Up™*](https://github.com/maxogden/yo-yo#yo-yojs), a paradigm to organize your frontend components**. In order to keep code maintainable, it encourages you to follow the following principles:
- Make your components pure. They receive arguments and compute a tree of DOM or [`virtual-dom`](https://github.com/Matt-Esch/virtual-dom#virtual-dom) nodes.
- Pass all data (often called "state") necessary to render the component as the first argument.
- Pass all functions that mutate this data (often called "actions"), as the second argument, grouped in an object.
This module enforces the pattern. **During development, it makes `data` immutable and asserts that every item in `actions` is a function.** In the production build, it will simply return the component, leading to almost no runtime overhead.
## Installing
```shell
npm install data-down-actions-up
```
## Usage
Consider this simplified user account component:
```js
const yo = require('yo-yo')
const account = (data, actions) => {
return yo `
${data.name}
`
}
```
Your components won't stay that beautiful however. Your codebase will become more chaotic as soon as you have tight deadlines or many developers.
Wrap the component to enforce *Data Down, Actions Up™*:
```js
const dataDownActionsUp = require('data-down-actions-up')
module.exports = dataDownActionsUp(account)
```
**If you bundle this, use [envify](https://github.com/hughsk/envify#readme) to get the production version of `dataDownActionsUp`**, which simply returns your `account` component directly.
### Bonus: memoization
A [memoized](https://en.wikipedia.org/wiki/Memoization#Overview) component will only rerender if you call it with different `data`. This tool helps you with that, but what *different* means is up to your component's logic.
Let's assume our `account` component from above is expensive to render, e.g. because it has to run a complex algorithm. We want to wrap it using `memoize`, so it only has to do expensive rerendering if `data` changed.
```js
const memoize = require('data-down-actions-up/memoize')
const compare = (dataFromLastCall, data) => {
return dataFromLastCall.name === data.name
&& dataFromLastCall.img === data.img
}
const memoizedAccount = memoize(account, compare)
```
`memoize` has the signature `memoize(component, [compare])`. If you don't pass a `compare` function, `data` and `dataFromLastCall` will be compared using `===`.
**Note that the extremely efficient `===` memoization only works if you have immutable `data`. If something changed, `data` will be a different object than `dataFromLastCall`.**
## Contributing
If you **have a question**, **found a bug** or want to **propose a feature**, have a look at [the issues page](https://github.com/derhuerst/location/issues).