Watch depth monitoring mode

watch Deep monitoring of — Listen for deeper data .

If it's an object , You need to conduct in-depth monitoring , In order to monitor the change of attributes in the object ：

data(){
    
	return{
    
		form :{
    
			name:'xxx',
			age:12
		}
	}
}
watch:{
    
	//  Only one listening object 
	form(){
    
		deep:true, //  Turn on depth monitoring 
		console.log(v.namge,v.age)
		immediate:true
	},
	//  Listen for an attribute of an object ：
 	'form.a': {
    
	   	handler(newName, oldName) {
    
	    	console.log('obj.a changed');
	   	},
	   	immediate: true
  	}
}

immediate:true Represents if in  wacth  It's stated in form after , I'll go ahead and execute the inside handler Method ,
deep： For deep monitoring , monitor form  and   His attributes .
handler： It's the previous monitoring function .
 adopt v.name and v.age Get the specific value in the object .