$ npm install --save sagen$ yarn add sagensagen is a state management library that uses a combination of individual repositories without root repositories.
You can create a store to manage the state. The store offers the following features:
-Detect changes in status when used in React -Combine multiple repositories to create one repository -Store management standardized with reducer and pattern -Store state comparison operation is managed to minimize the operation of unused state
You can display values that are not functions in store.
import { createStore } from 'sagen';
const numberStore = createStore(0);
const multipleStore = createStore({ num: 0, str: '' });The createStore function returns getState,setState functions.
In React, you can use useGlobalStore, useSagenState, and useSetSagenState to manage values.
The useGlobalStore Hook returns getter and setter as an array.
The usage method is the same as the React.useState Hook.
Changes from other configurations can be received as getter.
import { createStore, useGlobalStore } from 'sagen';
const store = createStore(0);
function Test() {
const [num, setNum] = useGlobalStore(store);
const incrementNum = () => {
setNum(curr => curr + 1);
};
return (
<div>
<p>num: {num}</p>
<button onClick={incrementNum}>
Increment
</button>
</div>
);
}useSagenState Hook returns getter of store.
import { createStore, useSagenState } from 'sagen';
const store = createStore(0);
function Test() {
const num = useSagenState(store);
return (
<p>num: {num}</p>
);
}useSetSagenState Hook returns setter of store.
import { createStore, useSetSagenState } from 'sagen';
const store = createStore(0);
function Test() {
const setNum = useSagenState(store);
const incrementNum = () => {
setNum(curr => curr + 1);
};
return (
<button onClick={incrementNum}>
Increment
</button>
);
}You can add arguments to useGlobalStore and useSagenState that return getter.
This is used for performance optimization.
You can pass selector to useGlobalStore and useSagenState.
This is mainly used for object stores, and allows you to subscribe only to the desired value of the object values.
The subscribed value only affects getter, and setter has information about the original value.
Since sagen operates only on the values that the component subscribes to,
it is not recommended to subscribe to values that are not being used.
import { createStore, useGlobalStore } from 'sagen';
const infoStore = createStore({
name: 'jungpaeng',
age: 22,
});
const ageSelector = store => store.age;
function Test() {
// Pass the ageSelector as the component uses only the age value.
const [age, setInfo] = useGlobalStore(infoStore, ageSelector);
const incrementAge = () => {
setInfo(curr => ({ ...curr, age: curr.age + 1 }));
};
return (
<div>
<p>age: {age}</p>
<button onClick={incrementAge}>
Increment
</button>
</div>
);
}You can pass equalityFn to useGlobalStore and useSagenState.
Used to detect if a component's subscribed value has changed.
Basically, === is used to compare, and shallowEqual is provided for comparing arrays, objects, etc.
import { createStore, useGlobalStore, shallowEqual } from 'sagen';
const infoStore = createStore({
name: 'jungpaeng',
use: 'typescript',
age: 22,
});
const selector = store => ({ name: store.name, age: store.age });
function Test() {
// Even if the unsubscribed use value changes, the component does not react.
const [info, setInfo] = useGlobalStore(infoStore, selector, shallowEqual);
const incrementAge = () => {
setInfo(curr => ({ ...curr, age: curr.age + 1 }));
};
return (
<div>
<p>name: {info.name}</p>
<p>age: {info.age}</p>
<button onClick={incrementAge}>
Increment
</button>
</div>
);
}You can manage it by adding a action to the store created with the createStore function.
Before using Dispatch, you need to define Action.
const store = createStore(0);
const storeAction = store.setAction((getter) => ({
INCREMENT: () => getter() + 1,
ADD: (num) => getter() + num,
}));The dispatch function passes the value created through action as an argument.
const store = createStore(0);
const storeDispatch = createDispatch(store);
const storeAction = store.setAction((getter) => ({
INCREMENT: () => getter() + 1,
ADD: (num) => getter() + num,
}));storeDispatch(storeAction.INCREMENT)
storeDispatch(storeAction.ADD, 100)sagen is compatible with Redux middleware.
Here is a simple logger middleware.
You can combine multiple middleware using composeMiddleware,
and pass it to the second argument of createStore.
import { createStore, composeMiddleware } from 'sagen';
const loggerMiddleware = store => next => action => {
console.log('Current state', store.getState());
console.log('Action', action);
next(action);
console.log('Next state', store.getState());
}
const store = createStore(0, composeMiddleware(loggerMiddleware));
// In Component ...
const [state, setState] = useGlobalStore(store);
setState(1);console log
Current state, 0
Action, 1
Next state, 1You can trigger an event when an update occurs.
This event cannot affect the state value.
import { createStore } from 'sagen';
const store = createStore(0);
// Returns a function that unsubscribes from event.
const removeEvent = store.onSubscribe((newState, prevState) => {
console.log(`prev: ${prevState}, new: ${newState}`);
});
// In Component ...
const [state, setState] = useGlobalStore(store);
setState(1);
// [console.log] prev: 0, new: 1
removeEvent();
setState(0);
// [console.log] EmptyMultiple stores' can be combined and managed as a single store`.
If you wish, you can also create and manage a single Root Store.
With composeStore, you can group store into a single store.
The integrated store is in a state of subscribing to the original store.
Changing values in one store affects values in other stores.
import { createStore, composeStore, useGlobalStore } from 'sagen';
const numStoreA = createStore(0);
const numStoreB = createStore(0);
const { store: numStoreAB } = composeStore({
a: numStoreA,
b: numStoreB,
});
function Test() {
const [store, setStore] = useGlobalStore(store);
const incrementA = () => {
setStore(curr => ({
...curr,
a: curr.a + 1,
}));
};
const incrementB = () => {
setStore(curr => ({
...curr,
b: curr.b + 1,
}));
};
return (
<div>
<p>A num: {store.a}</p>
<button onClick={incrementA}>
A Increment
</button>
<p>B num: {store.b}</p>
<button onClick={incrementB}>
B Increment
</button>
</div>
);
}sagen can be used without React.
Try the sagen-core library.
sagen is released under the MIT license.
Copyright (c) 2020 jungpaeng
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