One. Global API:
APIA global is not in the constructor, but declares global variables first or defines some new functions directly on VUE. VUE has built-in global APII, such as Vue.directive. Simply put, we define new functions with API functions provided by Vue outside the constructor.
Two. Vue.directive
1. Let's make a small example with custom designation to make the number green when initializing.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>vue.directive Custom directives</title>
<script type="text/javascript" src="https://unpkg.com/vue@2.5.16/dist/vue.js" ></script>
</head>
<body>
<h1>vue.directive Custom directives</h1>
<hr>
<div id="app">
<div v-jspang='color'>{{ num }}</div>
<p><button @click="add">ADD</button></p>
</div>
<p>
<button onclick ="unbind()">Untying</button>
</p>
<script>
//The following function is added to observe the fifth phase of the life cycle of custom instructions in the console
function unbind(){
app.$destroyed();
}
Vue.directive("jspang",{
bind:function(el,binding){//Bound
// console.log(el);
// console.log(binding);
// console.log(binding.name);
// console.log(binding.expression);
console.log('1 - bind');
el.style="color:"+binding.value;
},
inserted:function(){//Binding to nodes
console.log('2 - inserted');
},
update:function(){//Component update
console.log('3 - update');
},
componentUpdated:function(){//Component Update Completed
console.log('4 - componentUpdated');
},
unbind:function(){//Unbind
console.log('5 - unbind');
}
});
var app = new Vue({
el : '#app',
data : {
num : 10,
color : 'red'
},
methods:{
add:function(){
this.num++;
}
}
})
</script>
</body>
</html>2. Three parameters passed in the custom instruction:
el: Elements bound by instructions that can be used to manipulate DOM directly
binding: An object that contains a lot of information about instructions.
Vnode: Virtual node generated by Vue compilation
3. Life cycle of custom functions:
bind:function(){//Bound
console.log('1 - bind');
},
inserted:function(){//Binding to nodes
console.log('2 - inserted');
},
update:function(){//Component update
console.log('3 - update');
},
componentUpdated:function(){//Component Update Completed
console.log('4 - componentUpdated');
},
unbind:function(){//Unbind
console.log('5 - unbind');
}
//In specific examples, write
Vue.directive("jspang",{
bind:function(){//Bound
console.log('1 - bind');
},
inserted:function(){//Binding to nodes
console.log('2 - inserted');
},
update:function(){//Component update
console.log('3 - update');
},
componentUpdated:function(){//Component Update Completed
console.log('4 - componentUpdated');
},
unbind:function(){//Unbind
console.log('5 - unbind');
}
});
//Can be a specific stage function, add statements to achieve a specific effect. Like the green number on the article.