正文
[Redux] Implementing Store from Scratch
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Learn how to build a reasonable approximation of the Redux Store in 20 lines. No magic!
const counter = (state = 0, action) => {
switch (action.type) {
case 'INCREMENT':
return state + 1;
case 'DECREMENT':
return state - 1;
default:
return state;
}
}const createStore = (reducer) => {
let state;
let listeners = []; const getState = () => state; const dispatch = (action) => {
state = reducer(state, action);
listeners.forEach(listener => listener());
}; const subscribe = (listener) => {
listeners.push(listener);
return () => {
listeners = listeners.filter(l => l !== listener);
};
}; dispatch({}); return { getState, dispatch, subscribe };
};const store = createStore(counter);const render = () => {
document.body.innerText = store.getState();
};store.subscribe(render);
render();document.addEventListener('click', () => {
store.dispatch({ type: 'INCREMENT' });
});
