How to use v-model.number to implement data type conversion of input boxes in Vue

In Vue, v-model is an important instruction used to implement two-way binding. It allows us to easily synchronize user input to Vue's data attribute. But in some cases, we need to convert the data, such as converting the string type input by the user into a numeric type. In this case, we need to use the .number modifier of v-model to achieve this.

Basic usage of v-model.number

v-model.number is a modifier of v-model. It can convert the string type input by the user into a numeric type, and then This number is assigned to the data attribute. Its basic syntax is as follows:

<input v-model.number="dataPropertyName">

Among them, v-model.number is the modifier, and dataPropertyName is a data property name defined in the Vue instance.

Sample code:

HTML part:

<div id="app">
  <input type="text" v-model.number="age">
  <p>年龄：{{age}} 岁</p>
</div>

JavaScript part:

var vm = new Vue({
  el: "#app",
  data: {
    age: 0, //初始化age为0
  },
});

In the above code, we define an input box and a p Label, input box uses v-model.number to convert the string type entered by the user into a numeric type, and assigns this number to the age attribute in the Vue instance.

How v-model.number works

In the above example code, we bind the v-model.number instruction to the input box. This instruction has two functions:

1. Listen to user input events
2. Convert user input into numeric type

Specifically, v-model.number will monitor the input of the input box Event, whenever the content of the input box changes, this event will be triggered, and the value of the input box will be passed as a parameter to the age attribute defined in the Vue instance. However, since the value of the input box is of string type and the age attribute is of numeric type, v-model.number will automatically convert the string of the input box into a numeric type and assign this number to the age attribute.

It should be noted that v-model.number can only convert string type values ​​into numeric types. If the value of the input box is not a numeric string, then it will be converted into NaN.

Usage scenarios of v-model.number

v-model.number is suitable for scenarios where user input needs to be converted into numeric types, such as age, price, etc. It makes it easier for us to handle user input without the need for manual type conversion.

At the same time, v-model also has other modifiers, such as v-model.trim, v-model.lazy, etc., which can help us better respond to user input in different scenarios. , and control the behavior of the input box more flexibly.

Conclusion

In Vue, v-model.number is a very useful directive, which makes it more convenient for us to process user input without the need for manual type conversion. If your Vue application needs to process some numeric data, try using v-model.number to optimize your code.

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