昨天，我开始编写自己的绑定数据的方法。
玩它很有趣。
我认为它很漂亮，很有用。至少在我使用firefox和chrome进行的测试中，Edge也能正常工作。不确定其他人，但如果他们支持代理，我认为它会起作用。
https://jsfiddle.net/2ozoovne/1/
<H1>Bind Context 1</H1>
<input id='a' data-bind='data.test' placeholder='Button Text' />
<input id='b' data-bind='data.test' placeholder='Button Text' />
<input type=button id='c' data-bind='data.test' />
<H1>Bind Context 2</H1>
<input id='d' data-bind='data.otherTest' placeholder='input bind' />
<input id='e' data-bind='data.otherTest' placeholder='input bind' />
<input id='f' data-bind='data.test' placeholder='button 2 text - same var name, other context' />
<input type=button id='g' data-bind='data.test' value='click here!' />
<H1>No bind data</H1>
<input id='h' placeholder='not bound' />
<input id='i' placeholder='not bound'/>
<input type=button id='j' />
代码如下:
(function(){
if ( ! ( 'SmartBind' in window ) ) { // never run more than once
// This hack sets a "proxy" property for HTMLInputElement.value set property
var nativeHTMLInputElementValue = Object.getOwnPropertyDescriptor(HTMLInputElement.prototype, 'value');
var newDescriptor = Object.getOwnPropertyDescriptor(HTMLInputElement.prototype, 'value');
newDescriptor.set=function( value ){
if ( 'settingDomBind' in this )
return;
var hasDataBind=this.hasAttribute('data-bind');
if ( hasDataBind ) {
this.settingDomBind=true;
var dataBind=this.getAttribute('data-bind');
if ( ! this.hasAttribute('data-bind-context-id') ) {
console.error("Impossible to recover data-bind-context-id attribute", this, dataBind );
} else {
var bindContextId=this.getAttribute('data-bind-context-id');
if ( bindContextId in SmartBind.contexts ) {
var bindContext=SmartBind.contexts[bindContextId];
var dataTarget=SmartBind.getDataTarget(bindContext, dataBind);
SmartBind.setDataValue( dataTarget, value);
} else {
console.error( "Invalid data-bind-context-id attribute", this, dataBind, bindContextId );
}
}
delete this.settingDomBind;
}
nativeHTMLInputElementValue.set.bind(this)( value );
}
Object.defineProperty(HTMLInputElement.prototype, 'value', newDescriptor);
var uid= function(){
return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);
return v.toString(16);
});
}
// SmartBind Functions
window.SmartBind={};
SmartBind.BindContext=function(){
var _data={};
var ctx = {
"id" : uid() /* Data Bind Context Id */
, "_data": _data /* Real data object */
, "mapDom": {} /* DOM Mapped objects */
, "mapDataTarget": {} /* Data Mapped objects */
}
SmartBind.contexts[ctx.id]=ctx;
ctx.data=new Proxy( _data, SmartBind.getProxyHandler(ctx, "data")) /* Proxy object to _data */
return ctx;
}
SmartBind.getDataTarget=function(bindContext, bindPath){
var bindedObject=
{ bindContext: bindContext
, bindPath: bindPath
};
var dataObj=bindContext;
var dataObjLevels=bindPath.split('.');
for( var i=0; i<dataObjLevels.length; i++ ) {
if ( i == dataObjLevels.length-1 ) { // last level, set value
bindedObject={ target: dataObj
, item: dataObjLevels[i]
}
} else { // digg in
if ( ! ( dataObjLevels[i] in dataObj ) ) {
console.warn("Impossible to get data target object to map bind.", bindPath, bindContext);
break;
}
dataObj=dataObj[dataObjLevels[i]];
}
}
return bindedObject ;
}
SmartBind.contexts={};
SmartBind.add=function(bindContext, domObj){
if ( typeof domObj == "undefined" ){
console.error("No DOM Object argument given ", bindContext);
return;
}
if ( ! domObj.hasAttribute('data-bind') ) {
console.warn("Object has no data-bind attribute", domObj);
return;
}
domObj.setAttribute("data-bind-context-id", bindContext.id);
var bindPath=domObj.getAttribute('data-bind');
if ( bindPath in bindContext.mapDom ) {
bindContext.mapDom[bindPath][bindContext.mapDom[bindPath].length]=domObj;
} else {
bindContext.mapDom[bindPath]=[domObj];
}
var bindTarget=SmartBind.getDataTarget(bindContext, bindPath);
bindContext.mapDataTarget[bindPath]=bindTarget;
domObj.addEventListener('input', function(){ SmartBind.setDataValue(bindTarget,this.value); } );
domObj.addEventListener('change', function(){ SmartBind.setDataValue(bindTarget, this.value); } );
}
SmartBind.setDataValue=function(bindTarget,value){
if ( ! ( 'target' in bindTarget ) ) {
var lBindTarget=SmartBind.getDataTarget(bindTarget.bindContext, bindTarget.bindPath);
if ( 'target' in lBindTarget ) {
bindTarget.target=lBindTarget.target;
bindTarget.item=lBindTarget.item;
} else {
console.warn("Still can't recover the object to bind", bindTarget.bindPath );
}
}
if ( ( 'target' in bindTarget ) ) {
bindTarget.target[bindTarget.item]=value;
}
}
SmartBind.getDataValue=function(bindTarget){
if ( ! ( 'target' in bindTarget ) ) {
var lBindTarget=SmartBind.getDataTarget(bindTarget.bindContext, bindTarget.bindPath);
if ( 'target' in lBindTarget ) {
bindTarget.target=lBindTarget.target;
bindTarget.item=lBindTarget.item;
} else {
console.warn("Still can't recover the object to bind", bindTarget.bindPath );
}
}
if ( ( 'target' in bindTarget ) ) {
return bindTarget.target[bindTarget.item];
}
}
SmartBind.getProxyHandler=function(bindContext, bindPath){
return {
get: function(target, name){
if ( name == '__isProxy' )
return true;
// just get the value
// console.debug("proxy get", bindPath, name, target[name]);
return target[name];
}
,
set: function(target, name, value){
target[name]=value;
bindContext.mapDataTarget[bindPath+"."+name]=value;
SmartBind.processBindToDom(bindContext, bindPath+"."+name);
// console.debug("proxy set", bindPath, name, target[name], value );
// and set all related objects with this target.name
if ( value instanceof Object) {
if ( !( name in target) || ! ( target[name].__isProxy ) ){
target[name]=new Proxy(value, SmartBind.getProxyHandler(bindContext, bindPath+'.'+name));
}
// run all tree to set proxies when necessary
var objKeys=Object.keys(value);
// console.debug("...objkeys",objKeys);
for ( var i=0; i<objKeys.length; i++ ) {
bindContext.mapDataTarget[bindPath+"."+name+"."+objKeys[i]]=target[name][objKeys[i]];
if ( typeof value[objKeys[i]] == 'undefined' || value[objKeys[i]] == null || ! ( value[objKeys[i]] instanceof Object ) || value[objKeys[i]].__isProxy )
continue;
target[name][objKeys[i]]=new Proxy( value[objKeys[i]], SmartBind.getProxyHandler(bindContext, bindPath+'.'+name+"."+objKeys[i]));
}
// TODO it can be faster than run all items
var bindKeys=Object.keys(bindContext.mapDom);
for ( var i=0; i<bindKeys.length; i++ ) {
// console.log("test...", bindKeys[i], " for ", bindPath+"."+name);
if ( bindKeys[i].startsWith(bindPath+"."+name) ) {
// console.log("its ok, lets update dom...", bindKeys[i]);
SmartBind.processBindToDom( bindContext, bindKeys[i] );
}
}
}
return true;
}
};
}
SmartBind.processBindToDom=function(bindContext, bindPath) {
var domList=bindContext.mapDom[bindPath];
if ( typeof domList != 'undefined' ) {
try {
for ( var i=0; i < domList.length ; i++){
var dataTarget=SmartBind.getDataTarget(bindContext, bindPath);
if ( 'target' in dataTarget )
domList[i].value=dataTarget.target[dataTarget.item];
else
console.warn("Could not get data target", bindContext, bindPath);
}
} catch (e){
console.warn("bind fail", bindPath, bindContext, e);
}
}
}
}
})();
然后，设置，只需:
var bindContext=SmartBind.BindContext();
SmartBind.add(bindContext, document.getElementById('a'));
SmartBind.add(bindContext, document.getElementById('b'));
SmartBind.add(bindContext, document.getElementById('c'));
var bindContext2=SmartBind.BindContext();
SmartBind.add(bindContext2, document.getElementById('d'));
SmartBind.add(bindContext2, document.getElementById('e'));
SmartBind.add(bindContext2, document.getElementById('f'));
SmartBind.add(bindContext2, document.getElementById('g'));
setTimeout( function() {
document.getElementById('b').value='Via Script works too!'
}, 2000);
document.getElementById('g').addEventListener('click',function(){
bindContext2.data.test='Set by js value'
})
现在，我只添加了HTMLInputElement值绑定。
如果你知道如何改进，请告诉我。
