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⚙ How to install

npm

$ npm install --save sagen-core

yarn

$ yarn add sagen-core

🏃 Getting started

sagen-core is a state management library that can be used by defining each store.

1. Create a store

You can manage the state by creating a store. The store offers the following features:

• Manage store values using reducers
• Compute state using computed function
• Minimize operation of unused state by managing store state comparison operation

1-a. createStore

Non-function values can be stored in store.

import { createStore } from 'sagen-core';

const numberStore = createStore(0);
const multipleStore = createStore({ num: 0, str: '' });

2. State value management

The createStore function returns the getState and setState functions.

2-a. getState

The getState function returns the state value of store.

import { createStore } from 'sagen-core';

const store = createStore({ num: 0, str: '' });

store.getState(); // { num: 0, str: '' }

2-b. setState

The getState function changes the state value of store.

import { createStore } from 'sagen-core';

const store = createStore({ num: 0, str: '' });

store.setState({ num: 1, str: 'boo' });
store.getState(); // { num: 1, str: 'boo' }

If you need to modify some values in an object, you can edit them by writing the corresponding key.

import { createStore } from 'sagen-core';

const store = createStore({ num: 0, str: '' });

store.setState(({ num: 1 }));
store.getState(); // { num: 1, str: '' }

You can get the current value by passing a function to the argument of setState.

import { createStore } from 'sagen-core';

const store = createStore({ obj: { num: 0, str: '' } });

store.setState(curr => ({
    obj: { ...curr.obj, num: 1 },
}));

store.getState(); // { obj: { num: 1, str: '' } }

3. redux

You can manage values by passing reducer.

3-a. pass to reducer

const store = createStore(0);
redux<{ type: 'increase' | 'decrease'; by?: number }>(
    store,
    (state, { type, by = 1 }) => {
        switch (type) {
            case 'increase':
                return state + by;
            case 'decrease':
                return state - by;
        }
    },
);

3-b. storeDispatch

The redux function returns dispatch.

const store = createStore(0);
const storeDispatch = redux<{ type: 'increase' | 'decrease'; by?: number }>(
    store,
    (state, { type, by = 1 }) => {
        switch (type) {
            case 'increase':
                return state + by;
            case 'decrease':
                return state - by;
        }
    },
);

storeDispatch({ type: 'increase' });
store.getState(); // 1

4. computed

You can get a computed value based on the state value.

const store = createStore({ a: 0, b: 0 });
const computedStore = computed(
    store,
    (state) => {
        return {
            ab: state.a + state.b
        };
    },
);

computedStore.setState({ a: 50, b: 100 });
computedStore.getState(); // { a: 50, b: 100 }
computedStore.getComputed(); // { ab: 150 }

5. event subscribe

You can trigger an event when an update occurs.

This event cannot affect the state value.

5-a. onSubscribe

import { createStore } from 'sagen-core';

const store = createStore(0);

// Returns a function that unsubscribes from event.
const removeEvent = store.onSubscribe((newState, prevState) => {
  console.log(`prev: ${prevState}, new: ${newState}`);
});

store.setState(1);
// [console.log] prev: 0, new: 1

removeEvent();
store.setState(0);
// [console.log] Empty

Using in React

sagen is easier to use in React.

Try the sagen library.

📜 License

sagen-core is released under the MIT license.

Copyright (c) 2021 jungpaeng

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.