On the server:

Usage no npm install needed!

<script type="module">
  import 3livRijs from 'https://cdn.skypack.dev/@3liv/rijs';


Ripple Fullstack

On the server:


const ripple = require('rijs')({ dir: __dirname })

On the client:


<script src="/ripple.js"></script>

Run it:

$ node index.js

This starts up a server on a random port and statically serves your /pages directory. You can also specify a port to always use, or pass an existing HTTP server (e.g. from express).

Clients will then just be streamed the fine-grained resources they are using (i.e. everything is lazy loaded, no bundling, no over-fetching).

Ripple keeps clients/servers in sync by replicating an immutable log of actions in the background, and subsequently the view - or other modules - which are reactively updated when the local store is updated.

That's it! No boilerplate necessary, no build pipeline, no special transpilation, no magical CLI.

The basic API is:

ripple(name)        // getter
ripple(name, body)  // setter
ripple.on('change', (name, change) => { .. })



Let's add a (Web) Component to the page:


<script src="/ripple.js"></script>
+ <my-app></my-app>

Let's define the component:


export default () => ()

Ripple is agnostic to how you write your components, they should just be idempotent: a single render function.

This is fine:


export default (node, data) => node.innerHTML = 'Hello World!'

Or using some DOM-diff helper:


export default (node, data) => jsx(node)`<h1>Hello World</h1>`

Or using once/D3 joins:


export default (node, data) => {
    ('h1', 1)
      .text('Hello World')

For more info about writing idempotent components, see this spec.



The first parameter of the component is the node to update.

The second parameter contains all the state and data the component needs to render:

export default function component(node, data){ ... }
  • You can inject data resources by adding the name of the resources to the data attribute:

    <my-shop data="stock">
    export default function shop({ stock }){ ... }

    Declaring the data needed on a component is used to reactively rerender it when the data changes.

    Alternatively, you can use ripple.pull directly to retrieve a resource, which has similar semantics to dynamic import() (i.e. resolves from local cache or returns a single promise):

    const dependency = await pull('dependency')
  • The other option is to explicitly pass down data to the component from the parent:

      ('my-shop', { stock })

    The helper function will set the state and redraw, so redrawing a parent will redraw it's children. If you want to do it yourself:

    element.state = { stock }



You can set defaults using the ES6 syntax:

export default function shop({ stock = [] }){ ... }

If you need to persist defaults on the component's state object, you can use a small helper function:

export default function shop(state){ 
  const stock = defaults(state, 'stock', [])



Local state

Whenever you need to update local state, just change the state and invoke a redraw (like a game loop):

export default function abacus(node, state){ 
  const o = once(node)
      , { counter = 0 } = state

  o('span', 1)

  o('button', 1)
    .on('click.increment' d => {

Global state

Whenever you need to update global state, you can simply compute the new value and register it again which will trigger an update:

ripple('stock', {
  apples: 10
, oranges: 20
, pomegranates: 30

Or if you just want to change a part of the resource, use a functional operator to apply a finer-grained diff and trigger an update:

update('pomegranates', 20)(ripple('stock'))
// same as: set({ type: 'update', key: 'pomegranate', value: 20 })(ripple('stock'))

Using logs of atomic diffs combines the benefits of immutability with a saner way to synchronise state across a distributed environment.

Components are rAF batched by default. You can access the list of all relevant changes since the last render in your component via node.changes to make it more performant if necessary.



Dispatch an event on the root element to communicate changes to parents (node.dispatchEvent).



Routing is handled by your top-level component: Simply parse the URL to determine what children to render and invoke a redraw of your application when the route has changed:

export function app(node, data){
  const o = once(node)
      , { pathname } = location

  o('page-dashboard', pathname == '/dashboard')
  o('page-login', pathname == '/login')
    .on('popstate.nav', d => o.draw())

This solution is not tied to any library, and you may not need one at all.

For advanced uses cases, checkout decouter.



You can author your stylesheets assuming they are completely isolated, using the Web Component syntax (:host etc).

They will either be inserted in the shadow root of the element, or scoped and added to the head if there is no shadow.

By default, the CSS resource component-name.css will be automatically applied to the component component-name.

But you can apply multiple stylesheets to a component too: just extend the css attribute.


Folder Convention

All files in your /resources folder will be automatically registered (except tests etc). You can organise it as you like, but I recommend using the convention: a folder for each component (to co-locate JS, CSS and tests), and a data folder for the resources that make up your domain model.

├── data
│   ├── stock.js
│   ├── order.js
│   └── ...
├── my-app
│   ├── my-app.js
│   ├── my-app.css
│   └── test.js
├── another-component
│   ├── another-component.js
│   ├── another-component.css
│   └── test.js
└── ...

Hot reloading works out of the box. Any changes to these files will be instantly reflected everywhere.


Loading Resources

You can also get/set resources yourselves imperatively:

ripple(name)       // getter
ripple(name, body) // setter

Or for example import resources from other packages:


You can also create resources that proxy to fero) services too.



Resources are currently cached in localStorage.

This means even before any network interaction, your application renders the last-known-good-state for a superfast startup.

Then as resources are streamed in, the relevant parts of the application are updated.

Note: Caching of resources will be improved by using ServiceWorkers under the hood instead soon (#27)


Render Middleware

By default the draw function just invokes the function on an element. You can extend this without any framework hooks using the explicit decorator pattern:

// in component
export default function component(node, data){
  middleware(node, data)

// around component
export default middleware(function component(node, data){

// for all components
ripple.draw = middleware(ripple.draw)

A few useful middleware included in this build are:


This middleware reads the needs header and applies the attributes onto the element. The component does not render until all dependencies are available. This is useful when a component needs to define its own dependencies. You can also supply a function to dynamically calculate the required resources.

export default {
  name: 'my-component'
, body: function(){}
, headers: { needs: '[css=..][data=..]' }


If supported by the browser, a shadow root will be created for each component. The component will render into the shadow DOM rather than the light DOM.

Perf (Optional)

This one is not included by default, but you can use this to log out the time each component takes to render.

Other debugging tips:

  • Check ripple.resources for a snapshot of your application. Resources are in the tuple format { name, body, headers }.

  • Check $0.state on an element to see the state object it was last rendered with or manipulate it.



You can define a from function in the resource headers which will process requests from the client:

const from = (req, res) => 
  req.data.type == 'REGISTER' ? register(req, res)
: req.data.type == 'FORGOT'   ? forgot(req, res)
: req.data.type == 'LOGOUT'   ? logout(req, res)
: req.data.type == 'RESET'    ? reset(req, res)
: req.data.type == 'LOGIN'    ? login(req, res)
                              : false

module.exports = { 
  name: 'users'
, body: {}
, headers: { from } 

This can return a single value, a promise or a stream. On the client you make requests with ripple.send(name, type, value). This returns an awaitable stream.

You can also use the .subscribe API to subscribe to all or part of a resource. The key can be arbitrarily deep, and multiple keys will be merged into a single object.

ripple.subscribe(name, key)
ripple.subscribe(name, [keys])

Subscriptions are automatically deduplicated are ref-counted, so components can indepedently subscribe to the data they need without worrying about this.

Note that you can also use ripple.get instead of subscribe if you just want to get a single value and then automatically unsubscribe.


Ripple Minimal

If you have don't have backend for your frontend, checkout rijs/minimal which is a client-side only build of Ripple.

You can also adjust your own framework by adding/removing modules.



See rijs/docs for more guides, index of modules, API reference, etc