淺析vue中的MVVM實(shí)現(xiàn)原理

更新時(shí)間：2019年03月04日 10:36:13 作者：一席蓑衣笑眾

這篇文章主要介紹了淺析vue中的MVVM實(shí)現(xiàn)原理，小編覺得挺不錯(cuò)的，現(xiàn)在分享給大家，也給大家做個(gè)參考。一起跟隨小編過(guò)來(lái)看看吧

現(xiàn)成MVVM

菜單教程

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>Vue 測(cè)試實(shí)例 - 菜鳥教程(runoob.com)</title>
  <script src="https://unpkg.com/vue/dist/vue.js"></script>
</head>

<body>
  <div id="app">
    <input type="text" v-model="message">
    <p>{{ message }}</p>
  </div>

  <script>
    let vm = new Vue({
      el: '#app',
      data: {
        message: 'Hello Vue.js!'
      }
    })
  </script>
</body>

</html>

視圖影響數(shù)據(jù)

數(shù)據(jù)影響視圖

項(xiàng)目構(gòu)架

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>

<body>

</body>

</html>
<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>Vue 測(cè)試實(shí)例 - 菜鳥教程(runoob.com)</title>
  <script src="./js/mvvm.js"></script>
  <script src="./js/compile.js"></script>
</head>

<body>
  <div id="app">
    <input type="text" v-model="message">
    <div>{{message}}</div>
    <ul>
      <li></li>
    </ul>
    {{message}}
  </div>

  <script>
    let vm = new MVVM({
      el: '#app',
      data: {
        message: 'Hello Vue.js!'
      }
    })
  </script>
</body>

</html>

mvvm.html

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>

<body>

</body>

</html>
<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>Vue 測(cè)試實(shí)例 - 菜鳥教程(runoob.com)</title>
  <script src="./js/mvvm.js"></script>
  <script src="./js/compile.js"></script>
</head>

<body>
  <div id="app">
    <input type="text" v-model="message">
    <div>{{message}}</div>
    <ul>
      <li></li>
    </ul>
    {{message}}
  </div>

  <script>
    let vm = new MVVM({
      el: '#app',
      data: {
        message: 'Hello Vue.js!'
      }
    })
  </script>
</body>

</html>

mvvm.js

class MVVM {
  constructor(options) {
    this.$el = options.el;
    this.$data = options.data;

    if (this.$el) {
      new Compile(this.$el);
    }

  }
}

compile把dom節(jié)點(diǎn)，放在內(nèi)存中操作(到35分鐘)

class Compile {
  constructor(el, vm) {
    this.el = this.isElementNode(el) ? el : document.querySelector(el);
    this.vm = vm;
    if (this.el) {
      let fragment = this.node2frament(this.el);
      this.compile(fragment);
    }
  }

  //輔助方法
  isElementNode(node) {
    return node.nodeType === 1;
  }

  //核心方法
  compile(fragment) {
    let childNodes = fragment.childNodes;
    console.log(childNodes)
  }
  node2frament(el) {
    let fragment = document.createDocumentFragment();
    let firstChild;
    while (firstChild = el.firstChild) {
      fragment.appendChild(firstChild);
    }
    return fragment
  }
}

分類元素節(jié)點(diǎn)和文本節(jié)點(diǎn)(52分鐘)

class Compile {
  constructor(el, vm) {
    this.el = this.isElementNode(el) ? el : document.querySelector(el);
    this.vm = vm;
    if (this.el) {
      let fragment = this.node2frament(this.el);
      this.compile(fragment);
    }
  }

  //輔助方法
  isElementNode(node) {
    return node.nodeType === 1;
  }
  isDirective(name) {
    return name.includes('v-')
  }

  //核心方法
  compileElement(node) {
    let attrs = node.attributes;
    Array.from(attrs).forEach(arrt => {
      let attrName = attr.name;
      if (this.isDirective(attrName)) {
        let expr = attr.value;
      }
    })
  }
  compileText(node) {
    let text = node.textContent;
    let reg = /\{\{([^}]+)\}\}/g;
    if (reg.test(text)) {

    }
  }
  compile(fragment) {
    let childNodes = fragment.childNodes;
    Array.from(childNodes).forEach(node => {
      if (this.isElementNode(node)) {
        this.compile(node)
      } else {
        console.log('text', node)
      }
    })
  }
  node2frament(el) {
    let fragment = document.createDocumentFragment();
    let firstChild;
    while (firstChild = el.firstChild) {
      fragment.appendChild(firstChild);
    }
    return fragment
  }
}

元素節(jié)點(diǎn)

文本節(jié)點(diǎn)

把data中的數(shù)據(jù)，顯示在視圖上(到1:16分)

class Compile {
  constructor(el, vm) {
    this.el = this.isElementNode(el) ? el : document.querySelector(el);
    this.vm = vm;
    if (this.el) {
      let fragment = this.node2frament(this.el);
      this.compile(fragment);
      this.el.appendChild(fragment)
    }
  }

  //輔助方法
  isElementNode(node) {
    return node.nodeType === 1;
  }
  isDirective(name) {
    return name.includes('v-')
  }

  //核心方法
  compileElement(node) {
    let attrs = node.attributes;
    Array.from(attrs).forEach(attr => {
      let attrName = attr.name;
      if (this.isDirective(attrName)) {
        let expr = attr.value;
        let [, type] = attrName.split('-');
        CompileUtil[type](node, this.vm, expr)
      }
    })
  }
  compileText(node) {
    console.log(node)
    let expr = node.textContent;
    let reg = /\{\{([^}]+)\}\}/g;
    if (reg.test(expr)) {
      CompileUtil['text'](node, this.vm, expr)
    }
  }
  compile(fragment) {
    let childNodes = fragment.childNodes;
    Array.from(childNodes).forEach(node => {
      if (this.isElementNode(node)) {
        this.compileElement(node)
        this.compile(node)
      } else {
        this.compileText(node)
      }
    })
  }
  node2frament(el) {
    let fragment = document.createDocumentFragment();
    let firstChild;
    while (firstChild = el.firstChild) {
      fragment.appendChild(firstChild);
    }
    return fragment
  }
}


CompileUtil = {
  getVal(vm, expr) { // 獲取實(shí)例上對(duì)應(yīng)的數(shù)據(jù)
    expr = expr.split('.'); // [message,a]
    return expr.reduce((prev, next) => { // vm.$data.a
      return prev[next];
    }, vm.$data);
  },
  getTextVal(vm, expr) { // 獲取編譯文本后的結(jié)果
    return expr.replace(/\{\{([^}]+)\}\}/g, (...arguments) => {
      return this.getVal(vm, arguments[1]);
    })
  },
  text(node, vm, expr) { //文本處理
    let updateFn = this.updater['textUpdater'];
    let value = this.getTextVal(vm, expr);
    updateFn && updateFn(node, value)
  },

  model(node, vm, expr) {
    let updateFn = this.updater['modelUpdater'];
    updateFn && updateFn(node, this.getVal(vm, expr));
  },
  updater: {
    textUpdater(node, value) {
      node.textContent = value;
    },
    modelUpdater(node, value) {
      node.value = value;
    }
  }
}

v-model類型

 modelUpdater(node, value) {
      node.value = value;
      console.log(node)
      console.log(value)
      console.log(node.value)
    }

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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