frint-react


> React package for Frint

- Guide
- Installation
- Terminologies
- Usage
- Regions
- Region and data
- Observing components
- Multi-instance Apps
- API
- render
- hydrate
- observe
- Region
- RegionService
- streamProps
- ReactHandler

Guide

Installation

With npm:

``
$ npm install --save react react-dom prop-types frint-react
`

Via unpkg CDN:

`html










`

Terminologies

React:

* JSX: Syntatic sugar for writing JS in XML-like syntax.
* HyperScript: The function used in transpiled JSX code.
* Component: React Components.
* Container: Higher-Order Component, to pass down props to dumb components.

Reactive programming:

* Observable: As detailed in the spec, and implemented in RxJS.

Frint:

* Region: Component that can be embedded anywhere

Usage

We start by importing the necessary functions from the library:

`js
import React from 'react';
import { createApp } from 'frint';
import { render } from 'frint-react';
`

Now let's create our first Component:

`js
function Root() {
return (



);
}
`

Now we need to create our Root App, and assign the previously defined Component as our root component for the App:

`js
const RootApp = createApp({
name: 'MyRootApp',
providers: [
{
name: 'component',
useValue: Root
}
]
});
`

Now that we have everything ready, we can instantiate our app, and render it:

`js
window.app = new RootApp();
render(window.app, document.getElementById('root'));
`

The code above asumes your page has an element with an id root:

`html








`

Regions

The library already ships with a Region component, and a RegionService.

We use the concept of regions for defining areas in our Components, where other Apps can load themselves in.

For example, imagine the Root component of our Root App above, we can define a Region named sidebar as follows:

`js
import React from 'react';
import { Region } from 'frint-react';

function Root() {
return (



);
}
`

That's just defining the Region only. Let's now create an App, and assign it to the sidebar region:


`js
import { createApp } from 'frint';

function AppComponent() {
return (


I am App

);
}

const App = createApp({
name: 'MyApp',
providers: [
{
name: 'component',
useValue: AppComponent,
}
],
});
`

Now that we have our App defined, we can register it to our Root App:

`js
window.app.registerApp(App, {
regions: ['sidebar'], // name of regions to target
weight: 10, // the lower the number, the higher they would appear
});
`

Now when you refresh your browser, you would notice your App being rendered inside the Region sidebar.

Region and data

It is possible that when defining the Region with a name, you would also want to pass some data to it, so that whenever an App gets rendered inside it, the App would be able to access that data.

From the above example of sidebar Region, imagine us passing some data too via props:

`js
function Root() {
const data = {
foo: 'bar'
};

return (



);
}
`

That's only the Region component's implementation part. How do we access it from our App now?

Enter RegionService. This is a Service that we can pass in our App's providers list, allowing us to later have access to Region's props.

`js
import { RegionService } from 'frint-react';

const App = createApp({
name: 'MyApp',
providers: [
{
name: 'component',
useValue: AppComponent,
},
{
name: 'region',
useClass: RegionService, // useClass because RegionService will be instantiated
},
],
});
`

Once your App is registered and rendered, you can get access to your App instance, which can then allow you to deal with Region's props:

`js
const myApp = window.app.getAppInstance('MyApp');
const region = myApp.get('region');

// Region's data as an Observable
const regionData$ = region.getData$();

regionData$.subscribe((data) => {
console.log(data); // { foo: 'bar' }
});
`

We will discuss more in details how to get Region's props in your App's components via observe in the next section.

You can also use take data or other props passed to the Region as render prop:

`js
function Root() {
const data = {
foo: 'bar'
};

return (



);
}
`

Observing components

We encourage everyone to write their components in as dumb way as possible. Meaning, we just pass the props, and Components just render them. Nothing more.

But real-world applications are complex, and data can come from anywhere, at any time, asynchronously.

Enter observe. This is a function that we ship with the library for making your Components reactive.

A very simple example would be:

`js
function MyComponent(props) {
return (


Interval: {props.interval}


);
}
`

We just created a component, that prints out a prop called interval. Nothing fancy there. But we wish the interval to update itself every second. Instead of handling it from within the Component, we can do it with observe as follows:

`js
import { interval } from 'rxjs/observable/interval';
import { map } from 'rxjs/operators/map';
import { observe } from 'frint-react';

const MyObservedComponent = observe(function () {
const interval$ = interval(1000); // emits an integer every 1 second

return interval$
.pipe(
map(x => ({ interval: x })) // map the integer to a props-compatible object
);
})(MyComponent);
`

We have just made our simple Component reactive, by wrapping it with observe. Now it will continue to update the interval prop every second until the Component has unmounted itself.

$3

In previous example, we showed you how to access Region's data via RegionService. Now let's see how we can pass it to your App's component too.

All Region props but children and className are forwarded to the App's component by default. However, if you prefer a reactive approach:

`js
import { map } from 'rxjs/operators/map';
import { merge } from 'rxjs/operators/merge';
import { scan } from 'rxjs/operators/scan';

const ObservedAppComponent = observe(function (app, props$) {
// app is your App instance
// props$ is an Observable of props being passed by parent Component (if any)

// let's keep our first interval Observable too
const interval$ = interval(1000)
.pipe(
map(x => ({ interval: x }))
);

const region = app.get('region'); // the RegionService instance
const regionData$ = region.getData$()
.pipe(
map(regionData => ({ regionData: regionData }))
);

// now we have two observables, interval$ and regionData$.
// we need to merge them both into a single props-compatible object:
return interval$
.pipe(
merge(regionData$),
scan((props, emitted) => {
return {
...props,
...emitted,
};
}, {})
);
})(AppComponent);
`

When your App's component renders, latest props will be passed to it in this structure:

`js
{
// will keep updating every second,
interval: 1,

// will update whenever sidebar Region's props change
regionData: {
foo: 'bar'
}
}
`

$3

As the number of observables grow, it might be difficult to maintain your observe implementation. That's why we are also shipping a streamProps function in the library to make it easier for you:

`js
import { interval } from 'rxjs/observable/interval';
import { streamProps } from 'frint-react';

const MyObservedComponent = observe(function (app) {
return streamProps({}) // start streaming with a default plain object
// interval
.set(
interval(1000),
x => ({ interval: x }),
)

// region data
.set(
app.get('region').getData$(),
regionData => ({ regionData })
)

// plain object
.set({
key: 'value'
})

// key/value pairs
.set('myKey', 'myValue')

// return everything as a single merged Observable
.get$();
})(AppComponent);
`

The props available inside your Component would then be in this format:

`js
{
interval: 1,
regionData: { foo: 'bar' },
key: 'value',
myKey: 'myValue'
}
`

Multi-instance Apps

This is a use case where you have multiple instances of Region with the same name mounted in the DOM. And the apps rendered in them should have their own independent scoped instances too.

Think of a scenario where you have a TodoList, and you want a Region defined for each Todo item:

`js
function MyComponent() {
const todos = [
{ id: '1', title: 'First todo' },
{ id: '2', title: 'Second todo' },
{ id: '3', title: 'Third todo' },
];

return (



{todos.map((todo) => {
return (

• 
  

  {todo.title}

  name="todo-item"
data={{ todo }}
uniqueKey={todo-item-${todo.id}}
/>



);
})}



);
}
`

Now we may have an App that we want to be rendered in todo-item Regions.

Let's create an App, that will receive the todo object, and render the title in UPPERCASE format.

`js
import React from 'react';
import { createApp } from 'frint';
import { observe, RegionService } from 'frint-react';

function AppComponent(props) {
const { todo } = props;

return (


Todo in upper case: {todo.title.toUpperCase()}

);
}

const ObservedAppComponent = observe(function (app) {
return streamProps()
.set(
app.get('region').getData$(),
data => ({ todo: data.todo })
)
.get$();
})(AppComponent);

const App = createApp({
name: 'MyApp',
providers: [
{
name: 'component',
useValue: ObservedAppComponent
},
{
name: 'region',
useClass: RegionService
}
]
});
`

Now comes the part of registering our App as a multi-instance app:

`js
window.app.registerApp(App, {
regions: ['todo-item'],

// this tells Root App to treat this app as a multi-instance one
multi: true,
});
`

---

API

render

> render(app, node)

Renders a Root App in target DOM node.

$3

1. app (App): The Root App instance.
1. node (Element): The DOM Element where you want your App to render.

hydrate

> hydrate(app, node)

Hydrates a Root App in target DOM node.

observe

> observe(fn)(MyComponent)

$3

1. fn (Function): The function returning an Observable.
* The fn accepts two arguments:
* app: the instance of your Root App or the App in scope
* props$: an Observable of props being passed by parent component (if any)
* It should return an Observable or Object

$3

Function: that can be called with a Component to return an observed Component ready for embedding and rendering anywhere.

Region

> Region

The Region component.

$3

1. name (String): The name of the Region
1. data (Object): Data to be made available to rendered App
1. children (Function [optional]): Render prop function to render region component with passed props.
1. uniqueKey (String [optional]): Used when there are multiple Regions of the same name. It prop must be unique and fixed throughout the whole app.
1. className (String [optional]): The className used by Region wrapper element

RegionService

Exported from frint-component-handlers.

streamProps

Exported from frint-component-utils.

ReactHandler

> ReactHandler

Handler for React, according to the spec defined in frint-component-utils`.