詳解vue的資料binding原理
阿新 • • 發佈：2018-11-15
草蓆兩個頁面：
<!DOCTYPE html> <html> <head> <title>ideal</title> <meta charset="utf-8"> </head> <body> <div id="test"> <p>{{msg}}</p> <p>{{msg}}</p> <p>{{msg}}</p> <p>{{what}}</p> <p>{{hey}}</p> </div> <script> var bindingMark = 'data-element-binding' function Element (id, initData) { var self = this, el= self.el = document.getElementById(id) bindings = {} //內部暫存繫結資料及dom data = self.data = {} //儲存bingding資料並實現監控 content = el.innerHTML.replace(/\{\{(.*)\}\}/g, markToken) el.innerHTML = contentfor (var variable in bindings) { bind(variable); //將每個資料的名稱比如'msg'繫結到data } if (initData) { for (var variable in initData) { data[variable] = initData[variable] } } function markToken (match, variable) { bindings[variable] = {} //bindings裡儲存了資料來源的欄位比如bindings['msg'] return '<span ' + bindingMark + '="' + variable +'"></span>' } function bind (variable) { bindings[variable].els = el.querySelectorAll('[' + bindingMark + '="' + variable + '"]')//bindings裡再儲存msg繫結的元素 ;[].forEach.call(bindings[variable].els, function (e) { //刪除data-element-binding屬性 e.removeAttribute(bindingMark) }) Object.defineProperty(data, variable, { //es5觀察屬性 set: function (newVal) { [].forEach.call(bindings[variable].els, function (e) { bindings[variable].value = e.textContent = newVal //=>這裡才是實現的繫結,更新資料到dom並更新內部暫存資料 }) }, get: function () { return bindings[variable].value //取資料僅僅是內部暫存的資料 } }) } } var app = new Element('test', { msg: 'hello', what: 'hi' }) </script> </body> </html>
<!DOCTYPE html> <html> <head> <title>ideal</title> <meta charset="utf-8"> </head> <body> <input class="test" type="text" name="asd" onkeyup ="handleChange()" v-model="hey"> <input class="test" type="" name="" onkeyup ="handleChange()" v-model="msg"> <script> var bindingMark = 'data-element-binding' function Element (classa, initData) { var self = this, el = self.el = document.getElementsByClassName(classa),//多個input改為class bindings = {} data = self.data = {} for (var i = 0; i < el.length; i++) { content = el[i].outerHTML.replace(/v-model=\"(.*)\"/g, markToken); el[i].outerHTML = content } for (var variable in bindings) { bind(variable); } if (initData) { for (var variable in initData) { data[variable] = initData[variable] } } function markToken (match, variable) { bindings[variable] = {} return bindingMark + '="' + variable +'"' //內填一個span變為只改它的元素 } function bind (variable) { bindings[variable].els = document.querySelectorAll('[' + bindingMark + '="' + variable + '"]')//document獲取binding元素 ; Object.defineProperty(data, variable, { set: function (newVal) { [].forEach.call(bindings[variable].els, function (e) { bindings[variable].value = e.value = newVal //=>textContent改為input的value }) }, get: function () { return bindings[variable].value } }) } } var app = new Element('test', { msg: 'hello', hey:'aaa' }) function handleChange(e){ //增加v=>m的繫結 e = e || window.event var key = e.target.outerHTML.match(/data-element-binding=\"(.*)\"/)[1]; data[key] = e.target.value console.log(data.hey,data.msg); } </script> </body> </html>