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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>MVVM</title>
</head>
<body>
<div id="mvvm-app">
<input type="text" value="11212" v-model="someStr">
<input type="text" v-model="child.someStr">
<p :title="getHelloWord" :test="test">{{getHelloWord}}</p>
<p v-html="htmlStr"></p>
<button v-on:click="clickBtn">change model</button>
<button v-on:click="changeTest">changeTest</button>
</div>
</body>
</html>
function Observer(data) {
this.data = data;
this.walk(data);
}
function observe(obj) {
if (!obj || typeof obj !== 'object') {
return;
}
return new Observer(obj);
};
Observer.prototype = {
walk: function(data) {
for (var key in data) {
this.defineReactive(this.data, key, data[key])
}
},
defineReactive: function(data, key, val) {
var dep = new Dep();
observe(val);
Object.defineProperty(data, key, {
enumerable: true, // 可枚举
configurable: false, // 不能再define
get: function() {
if (Dep.target) {
dep.depend();
}
return val;
},
set: function(newVal) {
if (newVal === val) {
return;
}
val = newVal;
// 新的值是object的话,进行监听
observe(newVal);
// 通知订阅者
dep.notify();
}
});
}
};
var uid = 0;
function Dep() {
this.id = uid++;
this.subs = [];
}
Dep.prototype = {
addSub: function(sub) {
this.subs.push(sub);
},
depend: function() {
Dep.target.addDep(this);
},
removeSub: function(sub) {
var index = this.subs.indexOf(sub);
if (index != -1) {
this.subs.splice(index, 1);
}
},
notify: function() {
this.subs.forEach(function(sub) {
sub.update();
});
}
};
Dep.target = null;
function Watcher(vm, expOrFn, cb) {
this.cb = cb;
this.vm = vm;
this.expOrFn = expOrFn;
this.depIds = {};
if (typeof expOrFn === 'function') {
this.getter = expOrFn;
} else {
this.getter = this.parseGetter(expOrFn);
}
this.value = this.get();
}
Watcher.prototype = {
update: function() {
this.run();
},
run: function() {
var value = this.get();
var oldVal = this.value;
if (value !== oldVal) {
this.value = value;
this.cb.call(this.vm, value, oldVal);
}
},
addDep: function(dep) {
// 1. 每次调用run()的时候会触发相应属性的getter
// getter里面会触发dep.depend(),继而触发这里的addDep
// 2. 假如相应属性的dep.id已经在当前watcher的depIds里,说明不是一个新的属性,仅仅是改变了其值而已
// 则不需要将当前watcher添加到该属性的dep里
// 3. 假如相应属性是新的属性,则将当前watcher添加到新属性的dep里
// 如通过 vm.child = {name: 'a'} 改变了 child.name 的值,child.name 就是个新属性
// 则需要将当前watcher(child.name)加入到新的 child.name 的dep里
// 因为此时 child.name 是个新值,之前的 setter、dep 都已经失效,如果不把 watcher 加入到新的 child.name 的dep中
// 通过 child.name = xxx 赋值的时候,对应的 watcher 就收不到通知,等于失效了
// 4. 每个子属性的watcher在添加到子属性的dep的同时,也会添加到父属性的dep
// 监听子属性的同时监听父属性的变更,这样,父属性改变时,子属性的watcher也能收到通知进行update
// 这一步是在 this.get() --> this.getVMVal() 里面完成,forEach时会从父级开始取值,间接调用了它的getter
// 触发了addDep(), 在整个forEach过程,当前wacher都会加入到每个父级过程属性的dep
// 例如:当前watcher的是'child.child.name', 那么child, child.child, child.child.name这三个属性的dep都会加入当前watcher
if (!this.depIds.hasOwnProperty(dep.id)) {
dep.addSub(this);
this.depIds[dep.id] = dep;
}
},
get: function() {
Dep.target = this;
var value = this.getter.call(this.vm, this.vm);
Dep.target = null;
return value;
},
parseGetter: function(exp) {
if (/[^\w.$]/.test(exp)) return;
var exps = exp.split('.');
return function(obj) {
for (var i = 0, len = exps.length; i < len; i++) {
if (!obj) return;
obj = obj[exps[i]];
}
return obj;
}
}
};
function Compile(el, vm) {
this.$vm = vm;
this.$el = this.isElementNode(el) ? el : document.querySelector(el);
if (this.$el) {
this.$fragment = this.node2Fragment(this.$el);
this.compileElement(this.$fragment);
this.$el.appendChild(this.$fragment);
}
}
Compile.prototype = {
node2Fragment: function(el) {
var fragment = document.createDocumentFragment(),
child;
// 将原生节点拷贝到fragment
while (child = el.firstChild) {
fragment.appendChild(child);
}
return fragment;
},
compileElement: function(el) {
var childNodes = el.childNodes,
me = this;
[].slice.call(childNodes).forEach(function(node) {
var text = node.textContent;
var reg = /\{\{(.*)\}\}/;
if (me.isElementNode(node)) {
me.compile(node);
} else if (me.isTextNode(node) && reg.test(text)) {
me.compileText(node, RegExp.$1);
}
if (node.childNodes && node.childNodes.length) {
me.compileElement(node);
}
});
},
compile: function(node) {
var nodeAttrs = node.attributes,
me = this;
[].slice.call(nodeAttrs).forEach(function(attr) {
var attrName = attr.name;
if (me.isDirective(attrName)) {
var exp = attr.value;
var dir = attrName.substring(2);
// 事件指令
if (me.isEventDirective(dir)) {
compileUtil.eventHandler(node, me.$vm, exp, dir);
// 普通指令
} else {
compileUtil[dir] && compileUtil[dir](node, me.$vm, exp);
}
node.removeAttribute(attrName);
} else if (me.isBindAttr(attrName)) {
compileUtil.attr(node, me.$vm, attrName.slice(1), attr.value)
node.removeAttribute(attrName);
}
});
},
isBindAttr: function (attr) {
return attr.indexOf(':') == 0
},
compileText: function(node, exp) {
compileUtil.text(node, this.$vm, exp);
},
isDirective: function(attr) {
return attr.indexOf('v-') == 0;
},
isEventDirective: function(dir) {
return dir.indexOf('on') === 0;
},
isElementNode: function(node) {
return node.nodeType == 1;
},
isTextNode: function(node) {
return node.nodeType == 3;
}
};
// 指令处理集合
var compileUtil = {
text: function(node, vm, exp) {
this.bind(node, vm, exp, 'text');
},
attr: function (node, vm, attr, model) {
node.setAttribute(attr, this._getVMVal(vm, model))
new Watcher(vm, model, function(value, oldValue) {
node.setAttribute(attr, value)
});
},
html: function(node, vm, exp) {
this.bind(node, vm, exp, 'html');
},
model: function(node, vm, exp) {
this.bind(node, vm, exp, 'model');
var me = this,
val = this._getVMVal(vm, exp);
node.addEventListener('input', function(e) {
var newValue = e.target.value;
if (val === newValue) {
return;
}
me._setVMVal(vm, exp, newValue);
val = newValue;
});
},
class: function(node, vm, exp) {
this.bind(node, vm, exp, 'class');
},
bind: function(node, vm, exp, dir) {
var updaterFn = updater[dir + 'Updater'];
updaterFn && updaterFn(node, this._getVMVal(vm, exp));
new Watcher(vm, exp, function(value, oldValue) {
updaterFn && updaterFn(node, value, oldValue);
});
},
// 事件处理
eventHandler: function(node, vm, exp, dir) {
var eventType = dir.split(':')[1],
fn = vm.$options.methods && vm.$options.methods[exp];
if (eventType && fn) {
node.addEventListener(eventType, fn.bind(vm), false);
}
},
_getVMVal: function(vm, exp) {
var val = vm;
exp = exp.split('.');
exp.forEach(function(k) {
val = val[k];
});
return val;
},
_setVMVal: function(vm, exp, value) {
var val = vm;
exp = exp.split('.');
exp.forEach(function(k, i) {
// 非最后一个key,更新val的值
if (i < exp.length - 1) {
val = val[k];
} else {
val[k] = value;
}
});
}
};
var updater = {
textUpdater: function(node, value) {
node.textContent = typeof value == 'undefined' ? '' : value;
},
htmlUpdater: function(node, value) {
node.innerHTML = typeof value == 'undefined' ? '' : value;
},
classUpdater: function(node, value, oldValue) {
var className = node.className;
className = className.replace(oldValue, '').replace(/\s$/, '');
var space = className && String(value) ? ' ' : '';
node.className = className + space + value;
},
modelUpdater: function(node, value, oldValue) {
node.value = typeof value == 'undefined' ? '' : value;
}
};
function MVVM(options) {
this.$options = options || {};
var data = this._data = this.$options.data;
var me = this;
// 数据代理
// 实现 vm.xxx -> vm._data.xxx
for(var key in data) {
me._proxyData(key);
}
this._initComputed();
observe(data);
this.$compile = new Compile(options.el || document.body, this)
}
MVVM.prototype = {
$watch: function(key, cb, options) {
new Watcher(this, key, cb);
},
_proxyData: function(key) {
var me = this;
Object.defineProperty(me, key, {
configurable: false,
enumerable: true,
get: function proxyGetter() {
return me._data[key];
},
set: function proxySetter(newVal) {
me._data[key] = newVal;
}
});
},
_initComputed: function() {
var computed = this.$options.computed;
if (typeof computed !== 'object') {
throw new Error('computed is not object')
}
for(var key in computed) {
Object.defineProperty(this, key, {
get: typeof computed[key] === 'function' ? computed[key] : computed[key].get,
set: function() {}
});
}
}
};
var vm = new MVVM({
el: '#mvvm-app',
data: {
someStr: 'hellodf',
className: 'btn',
htmlStr: '<span style="color: #f00;">red</span>',
test: '123456789',
child: {
someStr: 'World !'
}
},
computed: {
getHelloWord: function() {
return this.someStr + ' ' + this.child.someStr;
}
},
methods: {
clickBtn: function(e) {
console.log('clicked')
var randomStrArr = ['childOne', 'childTwo', 'childThree'];
this.child.someStr = randomStrArr[parseInt(Math.random() * 3)];
},
changeTest: function () {
this.test = this.test.split('').reverse().join('')
}
}
});
vm.$watch('child.someStr', function() {
// console.log(arguments);
});
Also see: Tab Triggers