JavaScript/ex.html at master · mayu888/JavaScript · GitHub

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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>Document</title>
  </head>
  <body>
    <script src="http://localhost:3000/script1.js"></script>
    <script src="http://localhost:3000/script2.js" async></script>
    <div>111</div>
    <script defer>
      function combineReducers(reducers) {
        const initReducer = {};
        const reducerKeys = Object.keys(reducers);
        reducerKeys.forEach((key) => {
          initReducer[key] = reducers[key];
        });
        let hasChange = false;
        const nextState = {};
        function combination(state = {}, action) {
          const keysMap = Object.keys(initReducer);
          for (let i = 0; i < keysMap.length; i++) {
            const key = keysMap[i];
            const prev = state[key];
            const reducer = initReducer[key];
            const next = reducer(prevState, action);
            nextState[key] = next;
            hasChange = hasChange || prev !== next;
          }
          return hasChange ? nextState : state;
        }
      }

      const initState = {
        num: 1,
      };

      function myReducer(state = initState, action) {
        const type = action.type;
        if (type === "ADD") {
          return {
            ...state,
            num: state.num + 1,
          };
        }
        if (type === "CUTE") {
          return {
            ...state,
            num: state.num - 1,
          };
        }
      }

      function createStore(reducerFn) {
        let initState;
        let stack = [];
        const dispatch = (action) => {
          initState = reducerFn(initState, action);
          stack.forEach((item) => {
            item();
          });
        };
        const getState = () => {
          return initState;
        };

        const subscribe = (fn) => {
          stack.push(fn);
        };
        return { dispatch, getState, subscribe };
      }

      setTimeout(() => {
        console.log("js----1111");
      }, 1500);
    </script>
  </body>
</html>