• 13.vue组件

    vue组件(一)

    组件嵌套:

    1.全局嵌套:
    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
Vue.component("aaa",{
	template:`<div>组件A <bbb></bbb></div>`	
});//子组件放在父组件的模板里

Vue.component("bbb",{
	template:`<div>组件B</div>`
});
window.onload = function(){
	let vm = new Vue({
		el:"#app"	
	});	
};
</script>

</head>

<body>
<div id="app">
	<aaa></aaa>
	
</div>
</body>
</html>

    res:
    image

    2.局部嵌套:
    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
window.onload = function(){
	let vm = new Vue({
		el:"#app",
		components:{
			"aaa":{
				template:`<div>组件A<bbb></bbb></div>`,  
	//子组件必须放在父组件的属性里
				components:{
					"bbb":{
						template:`<div>组件B</div>`	
					}	
				}
			},
			/*"bbb":{
				template:`<div>组件B</div>`	
			}	*/ //错误
		}	
	});	
};
</script>

</head>

<body>
<div id="app">
	<aaa></aaa>
</div>
</body>
</html>

    res:
    image

    组件通信(重要)

    1、props/$emit

    1.数据的双向绑定:

    v-model后的变量名相同

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
window.onload = function(){
	let vm = new Vue({
		el:"#app",
		data:{
			msg:"abc"	
		}
	});	
};
</script>
</head>

<body>
<div id="app">
	<input v-model="msg" type="text" value=""/><br />
	<input v-model="msg" type="text" value=""/><br />
    {{msg}}<br />
	
	
</div>
</body>
</html>

    res:
    image

    2.父传子,子传父props/$emit, 用ev.target.value或事件监听

    (1)ev.target.value

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
Vue.component("mycomponent",{
	props:["msg"],
	template:`<div><input @input="show" type="text" :value="msg"/>{{msg}}</div>`,
	methods:{
		show(ev){
			console.log(22222);	
			this.$emit("abc",ev.target.value);
			//传子组件value值
		}	
	}
});
window.onload = function(){
	let vm = new Vue({
		el:"#app",
		data:{
			msg:"abc"		
		},
		methods:{
			fn(data){
				console.log(11111,data);
				this.msg = data;
			}	
		}
	});	
};
</script>
</head>

<body>
<div id="app">
	<input v-model="msg" type="text" value=""/>{{msg}}<br />
    <hr />
	<mycomponent :msg="msg" @abc="fn"></mycomponent>
</div>
</body>
</html>

    res:
    image
    (2)事件监听

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
Vue.component("mycomponent",{
	props:["msg"],
	template:`<div><input v-model="msg2" type="text" value=""/>{{msg}}</div>`,
	data(){
		return {msg2:this.msg}	
	},
	watch:{
		msg(){
			this.msg2 = this.msg;
		},
		msg2(){
			this.$emit("abc",this.msg2);
		}	
	}
});
window.onload = function(){
	let vm = new Vue({
		el:"#app",
		data:{
			msg:"abc"		
		},
		methods:{
			fn(data){
				console.log(11111,data);
				this.msg = data;
			}	
		}
	});	
};
</script>

</head>

<body>
<div id="app">
	<input v-model="msg" type="text" value=""/>{{msg}}<br />
    <hr />
	<mycomponent :msg="msg" @abc="fn"></mycomponent>
</div>
</body>
</html>

    res:
    image

    2.对象—— 引用

    子与父操控同一个对象

    1.父传子,子传父props,value
    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
Vue.component("mycomponent",{
	props:["msg"],
	template:`<div><input v-model="msg.value" type="text" value=""/>{{msg.value}}</div>`	
});
window.onload = function(){
	let vm = new Vue({
		el:"#app",
		data:{
			//msg:"abc"	
			msg:{value:"abc"}
			//对象--msg.value引用
		}
	});	
};
</script>

</head>

<body>
<div id="app">
	<input v-model="msg.value" type="text" value=""/>{{msg.value}}<br />
    <hr />
	<mycomponent :msg="msg"></mycomponent>
	
	
</div>
</body>
</html>

    res:
    image

    3.$children / $parent / $root

    1. $children
    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
Vue.component("aaa",{
	template:`<div>组件A----{{a}}</div>`	,
	data(){
		return {a:"a"}	
	}
});
Vue.component("bbb",{
	template:`<div>组件B</div>`	
});

window.onload = function(){
	let vm = new Vue({
		el:"#app",
		methods:{
			show(){
				//$children	
				console.log(this.$children);
				this.$children[0].$el.style.background = "red"
				this.$children[0].a = "abc"
			}	
		}	
	});	
};
</script>

</head>

<body>
<div id="app">
	<input @click="show" type="button" value=" 按钮" />
	<aaa></aaa>
	<bbb></bbb>
</div>
</body>
</html>

    res:
    image

    2.$parent
    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
Vue.component("aaa",{
	template:`<div @click="show">组件A----{{a}}</div>`,
	data(){
		return {a:"a"}	
	},
	methods:{
		show(){
			//parent/root
			console.log(this.$parent == this.$root);	
			//this.$parent.msg = "哈哈哈";
			this.$root.msg = "哈哈哈";
		}	
	}
});
Vue.component("bbb",{
	template:`<div>组件B</div>`	
});

window.onload = function(){
	let vm = new Vue({
		el:"#app",
		data:{
			msg:"Vue"
		},
		methods:{
			show(){
				
			}	
		}	
	});	
};
</script>

</head>

<body>
<div id="app">
	<input @click="show" type="button" value=" 按钮" />{{msg}}
    <hr />
	<aaa></aaa>
	<bbb></bbb>
</div>
</body>
</html>

    res:
    image

    3.$root
    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
Vue.component("aaa",{
	template:`<div @click="show">组件A----{{a}} <bbb></bbb></div>`,
	data(){
		return {a:"a"}	
	},
	methods:{
		show(){
			//parent/root
			console.log(this.$parent == this.$root);	
			//this.$parent.msg = "哈哈哈";
			this.$root.msg = "哈哈哈";
		}	
	}
});
Vue.component("bbb",{
	template:`<div @click.stop="show">组件B</div>`,
		methods:{
		show(){
			//parent/root
			console.log(this.$parent == this.$root);	
			this.$parent.a = "aa";
			this.$root.msg = "嘻嘻嘻";
		}	
	}
});

window.onload = function(){
	let vm = new Vue({
		el:"#app",
		data:{
			msg:"Vue"
		},
		methods:{
			show(){
				
			}	
		}	
	});	
};
</script>

</head>

<body>
<div id="app">
	<input @click="show" type="button" value=" 按钮" />{{msg}}
    <hr />
	<aaa></aaa>
</div>
</body>
</html>

    res:
    image

    4、ref/$refs

    this.$refs以数组的形式获取全部的ref

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
//ref
Vue.component("aaa",{
	template:`<div>组件A----{{a}} </div>`,
	data(){
		return {a:"a"}	
	}
});
Vue.component("bbb",{
	template:`<div>组件B</div>`,
});

window.onload = function(){
	let vm = new Vue({
		el:"#app",
		data:{
			msg:"Vue"
		},
		methods:{
			show(){
				console.log(this.$refs);
	//this.$refs以数组的形式获取全部的ref
				this.$refs.aaa.$el.style.background = "pink";
				this.$refs.aaa.a = "pink";
			}	
		}	
	});	
};
</script>

</head>

<body>
<div id="app">
	<input @click="show" type="button" value=" 按钮" />{{msg}}
    <hr />
	<aaa ref="aaa"></aaa>
	<bbb ref="bbb"></bbb>
</div>
</body>
</html>

    res:
    image

    5、eventBus事件总线

    let eventBus = new Vue();
    eventBus.$emit(sEv,data);
    eventBus.$on(sEv,data=>{})
    exp:

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
//事件总线——eventBus emit/on
Vue.component("aaa",{
	template:`<div @click="show">组件A----{{a}} </div>`,
	data(){
		return {a:"a"}	
	},
	created(){
		eventBus.$on("chagnea",data=>{
			this.a = data;
		});
	},
	methods:{
		show(){
			eventBus.$emit("chagneb","我想你了");	
		}	
	}
});
Vue.component("bbb",{
	template:`<div @click="show">组件B----{{b}}</div>`,
	data(){
		return {b:"b"}	
	},
	created(){
		eventBus.$on("chagneb",data=>{
			this.b = data;
		});
	},
	methods:{
		show(){
			eventBus.$emit("chagnea","我也想你了");	
		}
	}
});

let eventBus = new Vue();

window.onload = function(){
	let vm = new Vue({
		el:"#app",
		data:{
			msg:"Vue"
		},
		methods:{
			show(){
			}	
		}	
	});	
};
</script>

</head>

<body>
<div id="app">
	<aaa></aaa>
	<bbb></bbb>
</div>
</body>
</html>

    res:
    image

    6、sync

    sync --> this.$emit("updata:xxx",data);

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
//sync
Vue.component("mycomponent",{
	props:["msg"],
	template:`<div><input @input="show" v-model="msg2" type="text" value=""/>{{msg}}</div>`,
	data(){
		return {msg2:this.msg}	
	},
	methods:{
		show(){
			this.$emit("update:msg",this.msg2);
		}	
	}
});
window.onload = function(){
	let vm = new Vue({
		el:"#app",
		data:{
			msg:"abc"		
		},
		methods:{
			fn(data){
				this.msg = data;
			}	
		}
	});	
};
</script>

</head>

<body>
<div id="app">
	<input v-model="msg" type="text" value=""/>{{msg}}<br />
    <hr />
//@update:msg="fn",事件
	<mycomponent :msg="msg" @update:msg="fn" ></mycomponent>
// :msg.sync="msg",固定写法
	<mycomponent :msg.sync="msg" ></mycomponent>
</div>
</body>
</html>

    res:
    image
    image

    7、v-model

    v-model --> this.$emit("input",data);

    exp:自增

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
//sync
Vue.component("mycomponent",{
	template:`<div><input @click="show" type="button" value="plus"/></div>`,
	data(){
		return {count:0} 
	},
	methods:{
		show(){ 
		//"input"固定写法	this.$emit("input",++this.count);
		}	
	}
});
window.onload = function(){
	let vm = new Vue({
		el:"#app",
		data:{
			count:0	
		},
		methods:{
			show(data){
				console.log(1,data);
				this.count = data;	
			}	
		}
	});	
};
</script>

</head>

<body>
<div id="app">
	{{count}}
	<hr />
    <mycomponent v-model="count" ></mycomponent>

</div>
</body>
</html>

    res:
    image

    vue组件(二)

    1.创建组件

    1、全局 Vue.component
    2、局部 new Vue({components:{}});
    3、Vue.extend

    let VueComponent = Vue.extend(options);

    Vue.component("名字",VueComponent);

    返回值：Vue.extend、Vue.component 返回的都是VueComponent

    new VueComponent().$mount("#app");

    Vue.extend可以没有参数
    let VueComponent = Vue.extend();
    new VueComponent(options).$mount("#app");

    获取模板元素：
    let tmp = new VueComponent([options]).$mount().$el;

    document.body.appendChild(tmp);

    exp:

    ++Vue.extend++

    全局组件:
    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
//Vue.extend
//VueComponent
let mycomponent = Vue.extend({
	template:`<div>Vue.extend组件</div>`	
});

Vue.component("mycomponent",mycomponent);//("组件名",VueComponent)

window.onload = function(){
	let vm = new Vue({
		el:"#app",
	});	
};
</script>

</head>

<body>
<div id="app">
	<mycomponent></mycomponent>
</div>
</body>
</html>
    局部组件:
    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
//Vue.extend
let mycomponent = Vue.extend({
	template:`<div>Vue.extend组件</div>`	
});
//new Vue({components:{}});
window.onload = function(){
	let vm = new Vue({
		el:"#app",
		components:{mycomponent}
	});	
};
</script>

</head>

<body>
<div id="app">
	<mycomponent></mycomponent>
</div>
</body>
</html>

    //最大组件 Vue

    let VueComponent = Vue.extend(options);//new时不带参数
    let VueComponent = Vue.extend();//new时带参数

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
let Comp1 = Vue.extend({
	template:`<div>Vue.extend组件</div>`	
});

let Comp2 = Vue.extend();

console.log(1,Comp1);
console.log(2,Comp2);


window.onload = function(){
	//let oDiv = new Comp1().$mount().$el;
	//获取模板元素：
	let oDiv = new Comp2({
		template:`<div>new Comp2组件</div>`	
	}).$mount().$el;
	
	console.log(3,oDiv);
	
	document.body.appendChild(oDiv);
	
};
</script>

</head>

<body>
<div id="app">
 
</div>
</body>
</html>

    静态组件 动态组件

    必须有is
    静态--> is="组件的名称"
    动态--> :is="变量或者值 '组件的名称'"

    <div is="组件的名称"></div>
<div :is="变量或者值 '组件的名称'"></div>

    exp:

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>

Vue.component("aaa",{
	template:`<div>组件A</div>`	
});
Vue.component("bbb",{
	template:`<div>组件B</div>`	
});

window.onload = function(){
	let vm = new Vue({
		el:"#app",
		data:{
			comp:"aaa"	
		},
		methods:{
			toggle(){
				this.comp = this.comp=="aaa"?"bbb":"aaa";
			}	
		}	
	});
	
};
</script>

</head>

<body>
<div id="app">
	<input @click="comp='aaa'" type="button" value="组件A"/>
	<input @click="comp='bbb'" type="button" value="组件B"/>
	<input @click="toggle" type="button" value="toggle"/>
    <!-- 动态-->
 	<div :is="comp"></div>
 	 
</div>
</body>
</html>

    3.异步组件

    Vue.component(组件名称,(resolve,reject)=>{

	axios.get(url).then(res=>{
					
		resolve({
			template:res.data
		});
		
	});
});

    exp:

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script src="axios.js"></script>
<script>

Vue.component("mycomp",(resolve,reject)=>{
	axios.get("abc2.html").then(res=>{
		setTimeout(()=>{
			console.log(res.data);
			let oDiv = document.createElement("div");
			oDiv.innerHTML = res.data;
			//读取成功放到template
			resolve({
				//template:res.data	
				//template:oDiv.children[0].innerHTML	
				template:oDiv.children[0]	
			});
		},2000);
	});
});
window.onload=function(){
	let vm = new Vue({
		el:"#app",

	})
}
</script>

</head>

<body>
<div id="app">
	<mycomp></mycomp>
</div>
</body>
</html>

    4.组件的生命周期

    activated //激活
    deactivated //休眠

    必须跟 keep-alive标签

    <keep-alive>
	<div :is="'组件名称'"></div>
</keep-alive>

    exp:

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>

Vue.component("aaa",{
	template:`<div>组件A</div>`,
	activated(){
		console.log("A-----activated");//激活
	},
	deactivated(){
		console.log("A-----deactivated");//休眠
	},
	beforeDestroy(){
		console.log("A-----beforeDestroy");
	},
	destroyed(){
		console.log("A-----destroyed");
	},
});

Vue.component("bbb",{
	template:`<div>组件B</div>`,
	activated(){
		console.log("B-----activated");//激活
	},
	deactivated(){
		console.log("B-----deactivated");//休眠
	},
	beforeDestroy(){
		console.log("B-----beforeDestroy");
	},
	destroyed(){
		console.log("B-----destroyed");
	},
});

window.onload = function(){
	   vm = new Vue({
		el:"#app",
		data:{
			a:"aaa"	
		},
		methods:{
			toggle(){
				this.a = this.a == "aaa"?"bbb":"aaa";	
			}	
		}
	});	
};
</script>

</head>

<body>
<div id="app">
	<input @click="toggle" type="button" value="toggle"/>
    <keep-alive>
		<div :is="a"></div>
    </keep-alive>
</div>
</body>
</html>

    res:
    image

    错误的生命周期

    errorCaptured
    执行条件:
    只能捕获子组件的异常，无法捕获自己发生的错误！
    异常会冒泡！

    exp:

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
//异常会冒泡
Vue.component("aaa",{
	template:`<div>组件A <bbb></bbb></div>`,
	
	errorCaptured(){//捕获异常
		console.log("A-----errorCaptured");
	},
});

Vue.component("bbb",{
	template:`<div>组件B</div>`,
	data(){
		return {
			a	
			//a is not defined
		}	
	},
	errorCaptured(){
		console.log("B-----errorCaptured");
	}
});

window.onload = function(){
	   vm = new Vue({
		el:"#app",
		data:{
			//a	
		},
		errorCaptured(){
			console.log("Vue-----errorCaptured");
		}
	});	
};
</script>

</head>

<body>
<div id="app">
    <aaa></aaa>
    
</div>
</body>
</html>

    冒泡:bbb-->aaa-->app
    res:
    image

    5.组件渲染:

    Vue 推荐在绝大多数情况下使用 template 来创建你的 HTML。然而在一些场景中，你真的需要 JavaScript 的完全编程的能力，这就是 render 函数，它比 template 更接近编译器。

    render(createElement){
	return createElement(
	  "h1",   // tag name 标签名称
	  "标题" //内容: {属性:{属性值}}}
	)
}

    exp:

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
window.onload = function(){
	 let vm = new Vue({
		el:"#app",
		 render(createElement){
			return createElement(
			  "ul",   // tag name 标签名称
			  {
				 attrs: {
				   id: 'ul1'
			    },
				'class': {
					foo: true,
					bar: false
				 },  
				 style: {
					color: 'red',
					fontSize: '14px'
				 },
												  
			  },
			  [
			  	createElement("li","111"),
			  	createElement("li","222"),
			  	createElement("li","333"),
			  ]
			)
		 }
	});	
};
</script>

</head>

<body>
<div id="app">
   <!--
   	<ul>
    	<li>111</li>
    	<li>222</li>
    	<li>333</li>
    </ul>
   -->
    
</div>
</body>
</html>

    res:
    image

    6.混入

    合并.
    exp:

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>

let json1 = { 
	data:{
		msg:"abc",
		a:"a",
		b:"b",	
	},
	methods:{
		fn(){
			console.log("fn");	
		}	
	}  
};
let json2 = { 
	data:{
		c:"c",	
	},
	computed:{
		computedXXX(){
			console.log("computedXXX");	
		}	
	} ,
	watch:{
		c(){
			console.log("watch c");	
		}	
	}  
}
window.onload = function(){
	 let vm = new Vue({
		//mixins: [json],
		el:"#app",
		data:{
			msg:"Vue",
		},
		methods:{
			show(){
				console.log("show");
			}	
		},
		mixins: [json1,json2], 
	});	
	
	console.log(vm);
};
</script>

</head>

<body>
<div id="app"> 
</div>
</body>
</html>

    res:
    对与父组件已存在的实例,不会被改变
    image

    7.自定义指令

    v-xxx

    Vue.directive("xxx", function (el, binding) { 
  	console.log(el,binding);    
	el.style.color = "xxx"; 
})

    v-red 字体变红

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
Vue.directive("red", function (el, binding) {
  	console.log(el,binding);
	el.style.color = "red";
})

window.onload = function(){
	 let vm = new Vue({
		el:"#app",
	});	
	
	console.log(vm);
};
</script>

</head>

<body>
<div id="app"> 
	<div v-red>自定义指令</div>
</div>
</body>
</html>

    res:
    image

    v-color="'red'" 字体变红

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
Vue.directive("color", function (el, binding) {
  	console.log(el,binding);
	el.style.color = binding.value;
})


window.onload = function(){
	 let vm = new Vue({
		el:"#app",
	});	
	
};
</script>

</head>

<body>
<div id="app"> 

	<div v-color="'red'">自定义指令</div>
</div>
</body>
</html>

    res:
    image
    自定义样式style
    v-style="{'200px',height:'200px',background:'green'}"

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
/*
Vue.directive("style", function (el, binding) {
  	console.log(el,binding);
	for(let name in binding.value){
		el.style[name] = binding.value[name];
	}
})

*/
window.onload = function(){
	 let vm = new Vue({
		el:"#app",
		directives:{
			style(el, binding){
				console.log(el,binding);
				for(let name in binding.value){
					el.style[name] = binding.value[name];
				}
			}
		}
	});	
	
};
</script>

</head>

<body>
<div id="app"> 

	<div v-style="{'200px',height:'200px',background:'green'}">自定义指令</div>
</div>
</body>
</html>

    res:
    image

    自定义拖拽:v-drag

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>

Vue.directive("drag",{
	bind(el, binding){
		console.log("bind");
		el.style.position = "absolute";
		el.style.left = 0;
		el.style.top = 0;
		el.style.width = "100px";
		el.style.height = "100px";
		el.style.background = "red";
	},
	inserted(el, binding){
		el.onmousedown = function(ev){
			
			let disX = ev.clientX - el.offsetLeft;
			let disY = ev.clientY - el.offsetTop;
			document.onmousemove = function(ev){
				el.style.left = ev.clientX - disX + "px";
				el.style.top = ev.clientY - disY + "px";	
			};	
			document.onmouseup = function(){
				document.onmousemove = null;
				document.onmouseup = null;	
			};	
			return false;
		};
	},
	update(el, binding){
		console.log("update");
	},
	componentUpdated(el, binding){
		console.log("componentUpdated");
	},
	unbind(el, binding){
		console.log("unbind");
	},
		
})


window.onload = function(){
	 let vm = new Vue({
		el:"#app",
		data:{
			msg:"Vue",
			a:true,	
		},
		methods:{
			show(){
				this.a = false;
				this.msg = Math.random();	
			}	
		}
		
	});	
	
};
</script>

</head>

<body>
<div id="app"> 

	<div v-if="a" @click="show" v-drag>自定义指令 {{msg}}</div> 
</div>
</body>
</html>

    res:
    v-if: 与unbind
    image

    8.过滤器

    过滤器:
    https://cn.vuejs.org/v2/api/?#Vue-filter

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
//首字母大写
Vue.filter("capitalize", function (str) { 
  	return str.charAt(0).toUpperCase() + str.substring(1);
});
//字符串反转
/*Vue.filter("reverse", function (str) { 
  	return str.split("").reverse().join("");
});*/

window.onload = function(){
	 let vm = new Vue({
		el:"#app",
		data:{
			msg:"vue",
		},
		//字符串反转
		filters:{
			reverse(str){ 
				return str.split("").reverse().join("");
			}
		}
	});	
	
};
</script>

</head>

<body>
<div id="app"> 
	<input v-model="msg" type="text" value=""/><br />
    {{msg}}<br />
    {{msg|capitalize}}<br />
    {{msg|reverse}}<br />
    {{msg|reverse|capitalize}}<br />
    {{msg|capitalize|reverse}}<br />
</div>
</body>
</html>

    res:
    image

    9.nextTick

    nextTick https://cn.vuejs.org/v2/api/#Vue-nextTick
    将回调延迟到下次 DOM 更新循环之后执行。在修改数据之后立即使用它，然后等待 DOM 更新。它跟全局方法 Vue.nextTick 一样，不同的是回调的 this 自动绑定到调用它的实例上。

    <!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script src="vue.js"></script>
<script>
window.onload = function(){
	 let vm = new Vue({
		el:"#app",
		data:{
			msg:"vue",
		},
		methods:{
			show(){ 
				this.msg = Math.random(); 
				this.$nextTick(function(){
					let oSpan = document.getElementById("s1");
					console.log(oSpan.innerHTML);
				});
			}
		}
	});	
	
};
</script>

</head>

<body>
<div id="app"> 
	<input @click="show" type="button" value="按钮"/><br />
    <span id="s1">{{msg}}</span>
    
    
</div>
</body>
</html>

    res:
    ++不加nextTick,console.log(oSpan.innerHTML)中的结果是上一次的内容.++
    image
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  • 原文地址：https://www.cnblogs.com/zhongchao666/p/9463005.html
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