Vue
=======
前端框架、資料綁定
###### tags: `summertrain`

---

## 安裝 vue-cli

npm install -g @vue/cli
# OR
yarn global add @vue/cli

---

## 創建專案

vue create todo-list

選擇 CSS Pre-Processer(toggle with space)

---

## 使用 pug

npm i vue-cli-plugin-pug
# OR
yarn add vue-cli-plugin-pug

---

## 開啟網站

cd todo-list
npm run serve --port <port> --host <host>
# OR
yarn serve --port <port> --host <host>

打開 http://<host>:<port>

---

## 檔案結構

.
├── README.md
├── babel.config.js  # Preprocesser 設定
├── node_modules     # 安裝的模組
├── package.json     # 模組設定
├── public           # index.html 以及直接被存取的檔案
└── src              # source code

---

## 開始寫 Vue!

cd src/
vi App.vue

---

## Data binding
`{{ somedata }}`

<template lang="pug">                         
#app
  ul
    li {{ todo }}
</template>

<script>
  export default {
    data(){return{
      todo: '吃飯'
    }}
  }
</script>  

---

## Two-way Data bindings
`v-model='somedata'`

<template lang="pug">
#app
  input(type="text" placeholder="輸入待辦事項" v-model="todo.content")
  ul
    li
      input(type="checkbox" v-model="todo.completed")
      | {{ todo.content }}
</template>

<script>
  export default {
    data(){return{
      todo: {
        content: '睡覺',
        completed: false,
      }
    }}
  }
</script>

---

## Event Handling
`v-on:someEvent='someMethod()'`

input(type="text" placeholder="輸入待辦事項" v-model="newTodo" v-on:keyup.enter="addTodo(newTodo)")
ul
  li
    input(type="checkbox" v-model="todo.completed")
    | {{ todo.content }}

data(){return{
  newTodo: '',
  todo: {
    content: '睡覺',
    completed: false,
  }
}},

methods:{
  addTodo(newTodo){
    this.todo = {content: newTodo, completed: false}
  },
}

---

## List Rendering
`v-for='item in items'`

li(v-for='todo in todos')
  input(type="checkbox" v-model="todo.completed")
  | {{ todo.content }} - 
  a(v-on:click="removeTodo(todo)") 刪除

todos: [] 

methods:{
  addTodo(newTodo){
    this.todos.push({content: newTodo, completed: false})
  },
  removeTodo(todo){
    this.todos.splice(this.todos.indexOf(todo), 1);
  }
}

---

## Class and Style Bindings
`v-bind:class='{}'`

  li(v-bind:class='{ strikethrough: todo.completed }' v-for='todo in todos')

<style lang='sass'>
.strikethrough
  text-decoration: line-through
</style>

## 練習
1. 按下 enter 時 input 清空
2. 清空全部完成的事項