Connecting

In this section we will explore the three ways available in ConanJs to connect a component with a state. There are four ways of doing it:
Direct
We can use the Conan state object directly to connect to a component, using the method connect. This method will connect the whole state to the specified component 
Js
Js
import { counterState$ } from "../../../state/counter.state$";
​
{counterState$.connect(CounterDisplay)}
​
We can also use connectMap to connect to specific parts of the state:
Js
Ts
Js
import { counterState$ } from "../../../state/counter.state$";
​
counterState$.connectMap(CounterContainer, (data, actions) => ({
    decrementCounter: actions.decrement,
    incrementCounter: actions.increment
}));
​
counterState$.connectMap(CounterDisplay, data => ({
    counter: data.counter
}))
​
​
Ts
import {counterState$} from "../../../state/counter.state$";
​
counterState$.connectMap<CounterContainerProps> (
    CounterContainer,
    (data, actions)=>({
        decrementCounter: actions.decrement,
        incrementCounter: actions.increment
    })
)
​
counterState$.connectMap<CounterDisplayProps> (
    CounterDisplay,
    data=>({
        counter: data.counter
    })
)
​
HOC
Using the ConanJs component StateConnect, we can connect a React component with a Conan state:
Js
Ts
Js
export const CounterAppHOCAll = () => {
    return <StateConnect from={counterState$} into={CounterContainer}/>;
};
Ts
export const CounterAppHOCAll = (): React.ReactElement => {
    return <StateConnect<CounterData, CounterActions>
        from={counterState$}
        into={CounterContainer}
    />
}
And then use the state's data and actions within our React component. We can also use Conan's component ContextStateConnect, to achieve the same purpose, connect the whole state with a component:
​
Js
Ts
Js
<ContextStateConnect into={CounterDisplay}/>
Ts
<ContextStateConnect<CounterData, CounterActions>
    into={CounterDisplay}
/>
Inside the component, we can invoke the actions defined in the state, via props: 
this.props.actions.decrement
We can also access any data property via props: 
<h1>{this.props.data.counter}</h1>
​
Composition
We can also use compositions with the components contextStateConnect and contextStateMapConnect
contextStateConnect will connect the whole state:
Js
Ts
Js
import {stateConnect, contextStateConnect} from "conan-js-core";
​
stateConnect(counterState$, CounterContainer);
​
contextStateConnect(CounterDisplay)
Ts
import {ConnectedState, stateConnect, contextStateConnect} from "conan-js-core";
​
stateConnect<CounterData, CounterActions>(
    counterState$,
    CounterContainer
)
​
contextStateConnect<CounterData, CounterActions>(CounterDisplay)
​
contextStateMapConnect will connect only the specified properties:
Js
Ts
Js
import {stateMapConnect, contextStateMapConnect} from "conan-js-core";
​
stateMapConnect(counterState$, CounterContainer, (data, actions) => ({
    decrementCounter: actions.decrement,
    incrementCounter: actions.increment
}));
​
contextStateMapConnect(CounterDisplay, (data) => ({
    counter: data.counter
}))
Ts
import {ICallback, contextStateMapConnect, stateMapConnect} from "conan-js-core";
stateMapConnect<CounterData, CounterContainerProps, CounterActions>(
    counterState$,
    CounterContainer,
    (data, actions)=>({
        decrementCounter: actions.decrement,
        incrementCounter: actions.increment
    })
)
​
contextStateMapConnect<CounterData, CounterDisplayProps, CounterActions>(
    CounterDisplay,
    (data)=>({
        counter: data.counter
    })
)
​
Hooks
ConanJs has the hooks useConanState and useContextConanState to connect to a state:
Js
Ts
Js
import { counterState$ } from "../../../state/counter.state$";
import {useConanState, useContextConanState} from "conan-js-core";
​
const [, actions, ConanContext] = useConanState(counterState$);
const [data] = useContextConanState();
​
Ts
import {CounterActions, CounterData, counterState$} from "../../../state/counter.state$";
import {useConanState, useContextConanState} from "conan-js-core";
​
const [, actions, ConanContext] = useConanState <CounterData, CounterActions>(counterState$);
const [data] = useContextConanState <CounterData, CounterActions>();
​
​
Please take a look at this code sandbox to see al the subscription approaches working:
https://codesandbox.io/s/2zgr0
codesandbox.io
Live rendering
Composing State
Last updated 11 months ago