simplestate

Easy to learn and use replacement for MobX and Redux in React projects.

Installation

To install SimpleState in your project, run:

npm install @nextlevelcoder/simplestate

Usage

SimpleState can be used in Functional and Class React Components. The module includes a global SimpleState instance as simpleState, in addition to the SimpleState class.

SimpleState can also be subscribed to by functions, which can be used to modify derivative state.

Functional Components

Access the shared state "hello" using the variable "hello". Just as with the standard useState, you can pass a default value (true in the example).

import { simpleState } from '@nextlevelcoder/simplestate';

function MyComponent(props) {
    const [hello, setHello] = simpleState.useState('hello', true);
    . . . 
}

To set state you can use the returned set function (setHello) or SimpleState.setState as demonstrated in the Class Component section.

Class Components

Access the shared state "hello" as "this.state.hello".

import { simpleState } from '@nextlevelcoder/simplestate';

class MyComponent extends Component {
    componentWillMount() {
        simpleState.bindState(this, 'hello');
    }
    componentWillUnmount() {
        simpleState.unbindState(this);
        // To unbind just hello, use simpleState.unbindState(this, 'hello');
    }
    . . .
}

To bind multiple states, pass an array as the second param instead of a string:

import { simpleState } from '@nextlevelcoder/simplestate';

class MyComponent extends Component {
    componentWillMount() {
        simpleState.bindState(this, ['connected', 'latency']);
    }
    componentWillUnmount() {
        simpleState.unbindState(this);
        // To unbind multiple states (but not all states) call simpleState.unbindState(this, ['connected', 'latency]);
    }
    . . .
}

If you want to group related states in a single object on your state, you can pass an optional third parameter with the group name:

class MyComponent extends Component {
    componentWillMount() {
        // Access with this.state.sharedState.hello
        simpleState.bindState(this, 'hello', 'sharedState');
        // Access with this.state.networkState.online and this.state.networkState.latency
        simpleState.bindState(this, ['online', 'latency'], 'networkState');
    }
    componentWillUnmount() {
        // Group name isn't required to unbind, even when listing states.
        simpleState.unbindState(this);
    }
    . . .
}

To set state from a class component, you can call setState the same way you would for a component's state:

simpleState.setState({ hello: false });

Methods

import { simpleState } from '@nextlevelcoder/simplestate';

const mySubscriber = (state, value)=>{
    simpleState.setState('derivedState', value*2);
};

simpleState.subscribe('originalState', mySubscriber);
. . .

// If we ever want to stop updating derivedState
simpleState.unsubscibe('originalState', mySubscriber);

Multiple SimpleStates

SimpleState is a class you can instantiate as many times as you'd like.

SimpleStateMap

The best way to use multiple SimpleStates is with a SimpleStateMap. This is just a DefaultMap with a helper that creates new SimpleStates as its default value.

A global instance of SimpleStateMap can be imported as used as follows:

import { simpleStateMap } from '@nextlevelcoder/simplestate';

const accountState = simpleStateMap.getState('account');
const shoppingCartState = simpleStateMap.getState('shoppingCart');

Then you can use each SimpleState the way you used the global simpleState instance in the example above.

simpleStateMap is a global instance of SimpleStateMap. You can import and instantiate multiple SimpleStateMaps if you really want to complicate your code.

import { SimpleStateMap } from '@nextlevelcoder/simplestate';

const accountState = new SimpleStateMap();
const shoppingCartState = new SimpleStateMap();

// Export your manually create SimpleStateMaps to use them in other files.
export { accountState, shoppingCartState };

Manually

You can also declare and export multiple SimpleStates in a file shared by your components.

import { SimpleState } from '@nextlevelcoder/simplestate';

const accountState = new SimpleState();
const shoppingCartState = new SimpleState();

// Export your SimpleStates to use them in other files.
export { accountState, shoppingCartState };

Then just import your instances in the files that need to use them.