Accessing data in form rules with Vuetify: tips and tricks

Question

Accessing data in form rules with Vuetify: tips and tricks

Is it possible to access a data element within a rule?

Click here to see my code in action

I'm attempting to change the value of a data element on a text field rule within a Vuetify form.

While the rule itself is functioning properly, I'm encountering an issue when trying to access the data element. Specifically, this error message appears:

TypeError: Cannot set property 'disabled' of undefined

Below is a snippet of my code:

data: function() {
return {
  disabled: false,
  rules:{
    sellerId(value){
      if(value.length == 0){
        this.disabled = true;
        return "What are you trying to do here?";  
      }
      else{
        return true;
      }
    }
  },

Can someone help me identify what mistake I might be making?

javascript vue.js vuejs2 vue-component vuetify.js

Answer 1

Answer №1

Rules consist of a collection of functions. If you require the function to have access to the data property, you can define them as component methods:

data: function () {
  return {
    disabled: false
  }
},
methods: { 
  sellerId (value) {
    if (value.length === 0) {
      this.disabled = true;
      return "What is your intention here?";  
    } else {
      return true;
    }
  }
}

Then, in your Vuetify component:

<v-text-field :rules="[ sellerId ]"></v-text-field>

Answer 2

Rules consist of a collection of functions. If you require the function to have access to the data property, you can define them as component methods:

data: function () {
  return {
    disabled: false
  }
},
methods: { 
  sellerId (value) {
    if (value.length === 0) {
      this.disabled = true;
      return "What is your intention here?";  
    } else {
      return true;
    }
  }
}

Then, in your Vuetify component:

<v-text-field :rules="[ sellerId ]"></v-text-field>

Answer 3

Answer №2

Although this is not directly accessible within a rule function, you can still achieve the desired functionality by storing the Vue instance in a variable. This way, you can bring it into scope through closure.

vueInstance = new Vue({
    el: '#app',
    data: () => ({
        disabled: true,
        rules: [
            value => {
                if (value.length == 0) {
                    vueInstance.disabled = true;
                    return "What is your goal here?";  
                }
                else {
                    return true;
                }
            }
        ],
'''

Answer 4

Although this is not directly accessible within a rule function, you can still achieve the desired functionality by storing the Vue instance in a variable. This way, you can bring it into scope through closure.

vueInstance = new Vue({
    el: '#app',
    data: () => ({
        disabled: true,
        rules: [
            value => {
                if (value.length == 0) {
                    vueInstance.disabled = true;
                    return "What is your goal here?";  
                }
                else {
                    return true;
                }
            }
        ],
'''

Answer 5

Answer №3

One way to define the rules is by using it as a computed property :

data: function() {
    return {
      disabled: false,
      ...
    }
  },
  computed: {
    sellerIdRules() {
      return [
         (v) => {
        if (value.length == 0) {
          this.disabled = true;
          return "What are you trying to achieve?";
        } else {
          return true;
        } ]
      }
    }
  }

Answer 6

One way to define the rules is by using it as a computed property :

data: function() {
    return {
      disabled: false,
      ...
    }
  },
  computed: {
    sellerIdRules() {
      return [
         (v) => {
        if (value.length == 0) {
          this.disabled = true;
          return "What are you trying to achieve?";
        } else {
          return true;
        } ]
      }
    }
  }

Accessing data in form rules with Vuetify: tips and tricks

Answer №1

Answer №2

Answer №3

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