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HTML 

              
                h1 為什麼畫面沒有隨資料更新 — 深入 Vue 響應式原理筆記（物件部分）
hr
p.quotation 此篇文章為整理自 #[a(href="https://vuejs.org/v2/guide/reactivity.html") Vue 官網 Reactivity in Depth] 之筆記

h2 物件部分
hr
h3 畫面不會隨資料更新
#unregister-object(v-cloak)
    button(@click="addCount('dog')") addDogs
    button(@click="addCount('cat')") addCats
    button(@click="addCount('penguin')") addPenguin
    p dog {{ counter.dog }}, cat {{ counter.cat }}, penguin {{ counter.penguin }}
 
#register-object(v-cloak)
    h3 將需要響應式的資料都設定在 data 中
    button(@click="addCount('dog')") addDogs
    button(@click="addCount('cat')") addCats
    button(@click="addCount('penguin')") addPenguin
    p dog {{ counter.dog }}, cat {{ counter.cat }}, penguin {{ counter.penguin }}   



#dynamic-set-reactive-property(v-cloak)
    h3 動態添加響應式屬性（vm.$set）
    button(@click="addCount('dog')") addDogs
    button(@click="addCount('cat')") addCats
    button(@click="addCount('penguin')") addPenguin
    p dog {{ counter.dog }}, cat {{ counter.cat }}, penguin {{ counter.penguin }}   

#create-new-object(v-cloak)
    h3 建立一個新的物件(Object.assign())
    button(@click="addCount('dog')") addDogs
    button(@click="addCount('cat')") addCats
    button(@click="addCount('penguin')") addPenguin
    p dog {{ counter.dog }}, cat {{ counter.cat }}, penguin {{ counter.penguin }}   
    
h2 陣列部分
hr
!

CSS 

              
                $green: #41CEC0;
$vue: #41b883;
$blue: #35495e;
$purple: #A53860;
$red: #C63647;
$yellow: #FFDF2C;
$orange: #E96900;

[v-cloak]{
  display: none;
}
!

JS 

              
                /**
 * unregistaer-object
 **/

new Vue({
    el: "#unregister-object",
    data: {
        // 一開始沒有註冊 penguine，只註冊了 dog 和 cat
        counter: {
            dog: 0,
            cat: 0
        }
    },
    methods: {
        addCount(name) {
            this.counter[name]++;
        }
    },
    created() {
        // 在 created 的時候才建立 penguine 順便設值為 0
        this.counter.penguin = 0;
    },
    updated() {
        // 讓我們可以知道組件有被更新
        console.log("view updated");
    }
});

/**
 * register-object
 **/
new Vue({
    el: "#register-object",
    data: {
        counter: {
            dog: 0,
            cat: 0,
            penguin: 0 // 一開始就把要響應式變化的資料設定進來
        }
    },
    methods: {
        addCount(name) {
            this.counter[name]++;
        }
    },
    created() {
        // 在 created 的時候才建立 penguine 順便設值為 0
        this.penguin = 0;
    },
    updated() {
        // 讓我們可以知道組件有被更新
        console.log("view updated");
    }
});

/**
 * dynamic-set-reactive-property
 **/
new Vue({
    el: "#dynamic-set-reactive-property",
    data: {
        counter: {
            // 一開始沒有註冊 penguine，只註冊了 dog 和 cat
            dog: 0,
            cat: 0
        }
    },
    methods: {
        addCount(name) {
            this.counter[name]++;
        }
    },
    created() {
        // 在 created 的時候才建立 penguine 順便設值為 0
        // 使用 $set 動態新增響應式組件
        this.$set(this.counter, "penguin", 0);
    },
    updated() {
        // 讓我們可以知道組件有被更新
        console.log("view updated");
    }
});



/**
 * create-new-object
 **/
new Vue({
    el: "#create-new-object",
    data: {
        counter: {
            // 一開始沒有註冊 penguine，只註冊了 dog 和 cat
            dog: 0,
            cat: 0
        }
    },
    methods: {
        addCount(name) {
            this.counter[name]++;
        }
    },
    created() {
        // 透過建立新的物件來新增物件的屬性
        this.counter = Object.assign({}, this.counter, {
            penguin: 0,
            dog: 5
        })
    },
    beforeUpdate(){
        console.log(this.$el.querySelector('p').textContent)
        console.log("view beforeUpdate");
        this.$nextTick(function(){
            console.log(this.$el.querySelector('p').textContent)
        })
    },
    updated() {
        // 讓我們可以知道組件有被更新
        console.log("view updated");
    }
});
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