Sheva77
/
homework


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <title>24_practic_Redux_Basket</title>
    </head>
    <body>
        <button id="A">A</button>
        <button id="B">B</button>
        <h1 id="cart"></h1>
        <script>
            function createStore(reducer) {
                let state = reducer(undefined, {});
                let cbs = [];

                function dispatch(action) {
                    //if (typeof action === 'function'){
                    //return action(dispatch)
                    //}
                    let newState = reducer(state, action);
                    if (state !== newState) {
                        state = newState;
                        for (let cb of cbs) cb();
                    }
                }

                return {
                    getState() {
                        return state;
                    },
                    dispatch,
                    subscribe(cb) {
                        cbs.push(cb);
                        return () => {
                            cbs = cbs.filter(
                                (someElement) => someElement !== cb
                            );
                        };
                    },
                };
            }

            function cartReducer(state = {}, { type, id, count }) {
                if (type === "CART_ADD") {
                    return {
                        ...state,
                        [id]: count + (state[id] || 0),
                    };
                }

                if (type === "CART_DELETE") {
                    const { [id]: skip, ...newState } = state;
                    return newState;
                }

                return state;
            }
            const store = createStore(cartReducer);

            store.subscribe(() => console.log(store.getState()));

            const actionCartAdd = (id, count = 1) => ({
                type: "CART_ADD",
                id,
                count,
            });

            const actionCartDelete = (id) => ({
                type: "CART_DELETE",
                id,
            });

            A.onclick = () => store.dispatch(actionCartAdd("A"));
            B.onclick = () => store.dispatch(actionCartAdd("B"));
            store.subscribe(
                () => (cart.innerText = Object.keys(store.getState()).length)
            );
            // store.dispatch(actionCartAdd("C", 4));
            // store.dispatch(actionCartDelete("B"));

            // console.log(store.getState());
        </script>
    </body>
</html>