How to use dynamic parameters and calculated properties in Vue

1. Dynamic parameters

Starting from 2.6.0, you can use a JavaScript expression enclosed in square brackets as a directive argument:

<a v-bind:[attributeName]="url"> …

Here, attributeName will be dynamically evaluated as a JavaScript expression, and the resulting value will be used as the final parameter. For example, if your Vue instance has a data property attributeName with a value of "href", then this binding will be equivalent to v-bind:href.

Likewise, you can use dynamic parameters to bind a handler function to a dynamic event name:

<a v-on:[eventName]="doSomething"> …

In this example, when the value of eventName is "focus", v-on:[eventName] will be equivalent to v-on:focus.

Example:

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>Dynamic Parameters</title>
		<script src="vue.js"></script>
	</head>
	<body>
		<div id='app7'>
			<span v-on:[event_name]='dosomething'>{{msg}}</span>
		</div>
	</body>
	<script>
		var vm = new Vue({
			el:"#app7",
			data:{
				msg:100,
				event_name:'click'
			 },
			methods:{
				dosomething:function(){
					this.msg = this.msg + 1
				}
			}
		})
	</script>
</html>

2. Calculated properties

Expressions in templates are very convenient, but they are designed primarily for simple calculations. Putting too much logic in a template can make it cumbersome and difficult to maintain. For example:

{{ message.split('').reverse().join('') }}

At this point, the template is no longer just a simple declarative logic. You have to look at it for a while before you realize that what we want here is to display the reverse string of the variable message. It becomes even more difficult to handle when you want to include this flipped string in multiple places in your template.

So, for any complex logic, you should use computed properties.

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>Computed Properties</title>
		<script src="vue.js"></script>
	</head>
	<body>
		<div id = 'app'>{{value_add}}</div>
	</body>
	<script>
		var vm = new Vue({
			el:"#app",
			data:{
				value:100
			},
			
			computed:{ //Similar to methods value_add:function(){
					return this.value + 100
				}
			}
		})
	</script>
</html>

Summarize

This is the end of this article about the use of dynamic parameters and calculated properties in Vue. For more relevant Vue dynamic parameters and calculated properties content, please search for previous articles on 123WORDPRESS.COM or continue to browse the following related articles. I hope everyone will support 123WORDPRESS.COM in the future!

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