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# Redux 基本概念1
## Redux
## 概念
views點擊=>action => reducer => store =>回傳state給views
1.state統一由store保存，任何更新state都要告知store
2.讓views得到store中state的方法
```
1.使用connect讓最上層元件取得Provider中的store，再用props傳下去
2.使用store.getState
```
新增test1.html
## 簡單範例
```
Redux basic example
Clicked: 0 times
```
### Action
為一個函數返回一個物件，裡面至少會包含type
```
function addTodo(text) {
return {
type: ADD_TODO,
text: 'hihi'
}
}
```
### Reducer
Reducer為一個function裡面通常是寫入switch然後判斷剛才發出action的type，決定要做哪一種對應的switch case處理
```
function todoApp(state = initialState, action) {
switch (action.type) {
case ADD_TODO:
return Object.assign({}, state, {
todos: [
...state.todos,
{
text: action.text,
completed: false
}
]
})
default:
return state
}
}
```
上面的例子是，把原本的store中的state的todos陣列加入一筆新的資料
假設
```
var state = {
todos : [{text:'hihi',completed: false},{text:'okok',completed: false}]
}
```
我們可用
```
console.log(...state.todos)
```
之後
```
var final = Object.assign({}, state, {
todos: [
...state.todos,
{
text: 'yes',
completed: false
}
]
})
console.log(final);
```
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