createState

This is the basic unit of state-pool, it's a function which is used to create a state object, it accepts one parameter which is the initial value or initializer function.

// Signature
createState(initialValue: Any)

// Or

createState(initializer: () => Any)

Here is how to use it

import { createState } from 'state-pool';

const userName = createState("Yezy");

// Or if you have expensive computations during initialization you could use lazy initialization

function lazyInitializer(){
  // Perform expensive computation here
  
  return "Yezy";  // Return your initial state
}

const userName = createState(lazyInitializer);

Here are some of the mostly used methods available in a state object.

useState: This is used to subscribe a component to a state, it's a hook which should be used inside a react component.
```
// Signature
state.useState(config?: {selector: Function, patcher: Function});
```
useReducer: This too is used to subscribe a component to a state, it's also a hook which should be used inside a react component.
```
// Signature
state.useReducer(reducer: Function, config?: {selector: Function, patcher: Function});
```
getValue: This is used to get the value of a state
```
// Signature
state.getValue(selector?: Function);
```

setValue: This is used to set the value of a state

// Signature
state.setValue(value | stateUpdater: Any | Function, config?: {selector, patcher});

updateValue: This is used to update the value of a state

// Signature
state.updateValue(updater: Function, config?: {selector, patcher});

subscribe: This is used to listen to all changes from a state

// Signature
state.subscribe(observer: Function | Subscription: {observer, selector});

select: This is used to derive another state or select a deeply nested state
```
// Signature
state.select(selector: Function);
```
This returns DerivedState that you can subscribe to by calling subscribe on it as
```
// Signature
state.select(selector: Function).subscribe(observer: Function);
```

Below is an example showing all of them in action

import { createState } from 'state-pool';

const count = createState(0);

count.useState()  // This subscribe its component to count state

count.getValue()  // This will give 0

count.setValue(1)  // This set the value of count to 1

// This will print whenever count change
const unsubscribe = count.subscribe(val => console.log(val)) 

unsubscribe()  // This will unsubscribe the observer above

// An example for nested state
const user = createState({name: "Yezy", weight: 65});

user.updateValue(user => {user.weight += 1})  // This will increment the weight

// Select user name and subscribe to it,
// this will be printing whenever user name changes
user.select(user => user.name).subscribe(name => console.log(name));

info

createState should be used outside of a react component.

tip

createState is used to implement store.setState API.