ReduxのサンプルのTodoリストを真似てみる。Part.1

[Redux ExampleのTodo Listをはじめからていねいに(1)](https://qiita.com/xkumiyu/items/9dfe51d2bcb3bdb06da3)を参考にさせて頂いて、Reduxのコードを書いた。
#0.留意点
- 初心者の覚書です。
- 自分の環境で動くように参考にしたコードを適当に修正している。
- Windows10 64bit , PowerShellなどで動かしている。
- 見栄えを若干よくする為にbootstrap4を利用している。


#1.PowerShellで環境準備


```PowerShell:PowerShell
PS C:\Users\Taro\Desktop> mkdir ws


    ディレクトリ: C:\Users\Taro\Desktop


Mode                LastWriteTime         Length Name
----                -------------         ------ ----
d-----       2018/05/27     14:26                ws


PS C:\Users\Taro\Desktop> cd ws
PS C:\Users\Taro\Desktop\ws> npm init -y
Wrote to C:\Users\Taro\Desktop\ws\package.json:

{
  "name": "ws",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}


PS C:\Users\Taro\Desktop\ws> npm i -D babel-core babel-loader babel-preset-env babel-preset-react
npm notice created a lockfile as package-lock.json. You should commit this file.                                                                        es-commonjs
npm WARN babel-loader@7.1.4 requires a peer of webpack@2 || 3 || 4 but none is installed. You must install peer dependencies yourself.
npm WARN ws@1.0.0 No description
npm WARN ws@1.0.0 No repository field.

+ babel-preset-env@1.7.0
+ babel-core@6.26.3
+ babel-preset-react@6.24.1
+ babel-loader@7.1.4
added 128 packages from 67 contributors in 9.211s
[+] no known vulnerabilities found [2032 packages audited]

PS C:\Users\Taro\Desktop\ws> npm i -D webpack webpack-cli webpack-dev-server
npm WARN deprecated nomnom@1.8.1: Package no longer supported. Contact support@npmjs.com for more info.
npm WARN deprecated babel-preset-es2015@6.24.1: 🙌  Thanks for using Babel: we recommend using babel-preset-env now: please read babeljs.io/env to update!
npm WARN ws@1.0.0 No description                                                                                                                        es\extend-shallow
npm WARN ws@1.0.0 No repository field.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.4 (node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.4: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})

+ webpack-cli@2.1.4
+ webpack@4.9.1
+ webpack-dev-server@3.1.4
added 805 packages from 507 contributors in 29.534s
[+] no known vulnerabilities found [17167 packages audited]

PS C:\Users\Taro\Desktop\ws> npm install --save react  react-dom redux react-redux  prop-types
npm WARN ws@1.0.0 No description                                                                                                                        ments
npm WARN ws@1.0.0 No repository field.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.4 (node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.4: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})

+ react-redux@5.0.7
+ react-dom@16.4.0
+ redux@4.0.0
+ prop-types@15.6.1
+ react@16.4.0
added 17 packages from 86 contributors in 5.909s
[+] no known vulnerabilities found [17300 packages audited]

PS C:\Users\Taro\Desktop\ws> ni .babelrc , webpack.config.js, index.html


    ディレクトリ: C:\Users\Taro\Desktop\ws


Mode                LastWriteTime         Length Name
----                -------------         ------ ----
-a----       2018/05/27     14:28              0 .babelrc
-a----       2018/05/27     14:28              0 webpack.config.js
-a----       2018/05/27     14:28              0 index.html


PS C:\Users\Taro\Desktop\ws> mkdir src, dist


    ディレクトリ: C:\Users\Taro\Desktop\ws


Mode                LastWriteTime         Length Name
----                -------------         ------ ----
d-----       2018/05/27     14:29                src
d-----       2018/05/27     14:29                dist


PS C:\Users\Taro\Desktop\ws> cd src
PS C:\Users\Taro\Desktop\ws\src> mkdir actions, components, containers, reducers


    ディレクトリ: C:\Users\Taro\Desktop\ws\src


Mode                LastWriteTime         Length Name
----                -------------         ------ ----
d-----       2018/05/27     14:29                actions
d-----       2018/05/27     14:29                components
d-----       2018/05/27     14:29                containers
d-----       2018/05/27     14:29                reducers


PS C:\Users\Taro\Desktop\ws\src> cd ..
PS C:\Users\Taro\Desktop\ws> code .
```
#2.プロジェクトの設定ファイルを編集

```json:.bashrc
{
    "presets": [
        "env","react"
    ]
}
```
```json:package.json
{
  "name": "ws",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "build": "webpack --progress",
    "start": "webpack-dev-server --watch --progress"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "babel-core": "^6.26.3",
    "babel-loader": "^7.1.4",
    "babel-preset-env": "^1.7.0",
    "babel-preset-react": "^6.24.1",
    "webpack": "^4.9.1",
    "webpack-cli": "^2.1.4",
    "webpack-dev-server": "^3.1.4"
  },
  "dependencies": {
    "prop-types": "^15.6.1",
    "react": "^16.4.0",
    "react-dom": "^16.4.0",
    "react-redux": "^5.0.7",
    "redux": "^4.0.0"
  }
}

```
```javascript:webpack.config.js
const path = require('path');

module.exports = {
  mode:'development',
    entry: './src/index.js',
    output: {
      path: path.join(__dirname,'dist'),
      filename: 'index.js',
      publicPath: path.join(__dirname,'dist')
    },
    devtool: '#source-map',
    devServer: {
      contentBase: './',
      port: 8080
    },
    module: {
      rules: [
        { test: /\.js$/, exclude: /node_modules/, loader: 'babel-loader' }
      ]
    }
  };
  
```

#3.ファイルを大まかに作成

```html:プロジェクトディレクトリ/index.html
<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title>ReduxでTodoリストを作ろう</title>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
  </head>
  <body>
    <div id="root"></div>
    <script src="dist/index.js"></script>
  </body>
</html>
```
```jsx:components/App.js
import React from 'react';

const App = ()=>(
    <h1>ダミーH1</h1>
)

export default App;
```

```javascript:reducers/index.js
const reducers =  (state,action)=>{
    return state;
}
export default reducers;
```

```jsx:./index.js
import React from 'react';
import ReactDOM from 'react-dom';
import { Provider } from 'react-redux';
import reducers from './reducers'
import { createStore } from 'redux';
import App from './components/App'

let store = createStore(reducers);

ReactDOM.render(
    <Provider store={store}>
        <App />
    </Provider>,
    document.getElementById('root')
);

```
```text:コマンド実行
npm run build
npm run start
```
[http://localhost:8080](http://localhost:8080/)で動作確認

[ソースコード 01](https://github.com/tkarasuma/JavaScript/tree/master/ws_01)

#3.stateをTodo用に加工し、コンソールで確認

##actionCreatorをつくる
actionを作る関数

```javascript:actions/index.js
let nextTodoId=0
const addTodo= (text)=>{
    return{
        type:'ADD_TODO',
        id:nextTodoId++,
        text

    }
}
export default addTodo;
```
##reducersを修正

actionとstateを引数にとり、なかでアプリケーションのロジックを駆使して新しいstateを返す関数をつくる。名前もreducersからtodoに変更している。

```javascript:reducers/index.js
const todo = (state, action) => {
    switch (action.type) {
        case 'ADD_TODO':
            return {
                id: action.id,
                text: action.text
            }
        default:
            return state;
    }
}
export default todo;
```

index.jsを修正

```jsx:index.js
import React from 'react';
import ReactDOM from 'react-dom';
import { Provider } from 'react-redux';
import todo from './reducers'
import { createStore } from 'redux';
import App from './components/App'
import addTodo from './actions'

let store = createStore(todo);
store.dispatch(addTodo('Todo 1番目'));
console.log(store.getState());

ReactDOM.render(
    <Provider store={store}>
        <App />
    </Provider>,
    document.getElementById('root')
);

```
[http://localhost:8080](http://localhost:8080/)で動作確認。コンソールにstateが出てくればOK

[ソースコード 02](https://github.com/tkarasuma/JavaScript/tree/master/ws_02)

###追記
編集リクエストで　シンタックスハイライトのところ、JavaScript->jsxして頂いた方、ありがとうございます。2018/05/28 16:31