Vue, how to use a v-model

The v-model Vue directive allows us to create a two-way binding.

You can bind a form input element for example, and make it change the Vue data property when the user changes the content of the field:

<input v-model="message" placeholder="Enter a message">
<p>Message is: {{ message }}</p>

<select v-model="selected">
  <option disabled value="">Choose a fruit</option>
  <option>Apple</option>
  <option>Banana</option>
  <option>Strawberry</option>
</select>
<span>Fruit chosen: {{ selected }}</span>

Handy directive modifiers

To make the model update when the change event occurs, and not any time the user presses a key, you can use v-model.lazy instead of just v.model.

Working with input fields, v-model.trim is useful because it automatically removes whitespace.

And if you accept a number instead than a string, make sure you use v-model.number.

Nested properties

Say you have a shopping cart, and you have a component that holds a form to add a product:

<template>
  <div class="">
    <h1>Add Product</h1>
    <label>Name</label>: <input>
    <label>Description</label>: <textarea></textarea>
    <button @click="addProduct">Add</button>
  </div>
</template>

<script>
export default {
  name: 'AddProduct',
  data() {
    return {
      product: {
        name: '',
        description: ''
      }
    }
  },
  methods: {
    addProduct() {
      console.log(this.product)
    }
  }
}
</script>

To make the form update the inner properties of the product state value, you use product.*:

<label>Name</label>: <input v-model="product.name">
<label>Description</label>: <textarea v-model="product.description"></textarea>