Category: Vue

In Vue 3’s Composition API, you can watch a store value by using the watch function provided by Vue.

To do this we write:

import { ref, watch } from 'vue';
import { useStore } from 'vuex'; // If you're using Vuex

export default {
  setup() {
    const store = useStore(); // Assuming you're using Vuex

    // Define a ref to store the value you want to watch
    const myStoreValue = ref(store.state.someValue);

    // Watch for changes in the store value
    watch(
      () => store.state.someValue, // Getter function
      (newValue, oldValue) => {
        // This callback will be triggered whenever the value changes
        console.log('Store value changed:', newValue);
        // Update the ref with the new value
        myStoreValue.value = newValue;
      }
    );

    // You can also use watchEffect if you don't need access to the old value
    // watchEffect(() => {
    //   myStoreValue.value = store.state.someValue;
    // });

    return {
      myStoreValue
    };
  }
};

In this example, we import ref and watch from Vue.

We import useStore from Vuex to access the store instance.

Inside the setup() function, we define a reactive reference (myStoreValue) to store the value from the store.

We use the watch function to watch for changes to the store’s value.

The first argument to watch is a getter function that returns the value we want to watch (in this case, store.state.someValue).

The second argument is a callback function that will be executed whenever the value changes.

Inside this callback, you can perform any actions you need to with the new value.

Finally, we return myStoreValue from the setup() function so it can be used in the template.

This setup will ensure that myStoreValue always reflects the current value of store.state.someValue, and the callback will be triggered whenever someValue changes in the store.

When using Vue.js with Vuetify for form validation, you can define rules for matching inputs using the Vuetify’s validation system.

To define ES6 rules for matching inputs we can:

Define Rules Object

Create a rules object where you define validation rules for each input field that needs to be matched. You can use ES6 syntax to define these rules.

Attach Rules to Inputs

Attach the rules to the respective input fields in your form using Vuetify’s rules prop.

Define Custom Validation Function (if necessary)

If the built-in rules are not sufficient for your matching criteria, you can define a custom validation function and use it as a rule.

For example we write:

<template>
  <v-form ref="form" @submit.prevent="submitForm">
    <v-text-field
      v-model="password"
      label="Password"
      type="password"
      :rules="passwordRules"
    ></v-text-field>
    <v-text-field
      v-model="confirmPassword"
      label="Confirm Password"
      type="password"
      :rules="[confirmPasswordRules, matchPasswordRule]"
    ></v-text-field>
    <v-btn type="submit">Submit</v-btn>
  </v-form>
</template>

<script>
export default {
  data() {
    return {
      password: '',
      confirmPassword: ''
    };
  },
  computed: {
    passwordRules() {
      return [
        value => !!value || 'Password is required',
        value => (value && value.length >= 8) || 'Password must be at least 8 characters'
      ];
    },
    confirmPasswordRules() {
      return [
        value => !!value || 'Confirm Password is required'
      ];
    }
  },
  methods: {
    matchPasswordRule(value) {
      return value === this.password || 'Passwords do not match';
    },
    submitForm() {
      // Submit logic here
    }
  }
};
</script>

In this example, we have two text fields for password and confirm password.

We define validation rules for each field using computed properties passwordRules and confirmPasswordRules.

For the confirm password field, we use a custom validation function matchPasswordRule to check if the value matches the password field.

We attach these rules to the input fields using the :rules prop.

By following this approach, you can define ES6 rules for matching inputs with Vue Vuetify Form Validation.

Adjust the rules and validation logic according to your specific requirements.

If you’re encountering $router as undefined in a Vue.js application, it typically means that the router instance is not properly configured or accessible within the component where you’re trying to use it. Here are some steps to troubleshoot and fix this issue:

Ensure Vue Router is properly installed

Make sure that you have Vue Router installed in your project. You can install it via npm or yarn:

npm install vue-router

or

yarn add vue-router

Check router configuration

Verify that you have properly configured your Vue Router instance in your main Vue application file (usually main.js or app.js).

import Vue from "vue";
import VueRouter from "vue-router";
import App from "./App.vue";
import routes from "./routes"; // Your route configuration file

Vue.use(VueRouter);

const router = new VueRouter({
  routes,
  mode: "history", // or 'hash' depending on your preference
});

new Vue({
  router,
  render: (h) => h(App),
}).$mount("#app");

Check component usage

Ensure that you’re accessing $router within a Vue component and not outside of it.

$router is typically accessed within Vue components or Vuex store actions/mutations.

Double-check component registration

If you’re using Vue single-file components (.vue files), make sure that the component in which you’re trying to use $router is properly registered with the Vue Router.

You should use <router-view> or this.$router.push() within these components.

Scoped access

If you’re trying to access $router within a nested component, make sure that the parent component has properly passed down the router instance via props or through a Vuex store.

Ensure Vue Router is properly imported

In the component where you’re trying to use $router, make sure that you have imported Vue Router and that it’s properly referenced.

import VueRouter from 'vue-router';

Check for typos

Sometimes, $router may be misspelled, so double-check your code for any spelling mistakes.

Use this.$router

Within Vue components, ensure that you’re accessing $router using this.$router syntax.

Check for asynchronous initialization

If you’re trying to access $router before it’s fully initialized, consider using lifecycle hooks like mounted() to ensure that the router is available before accessing it.

By following these steps, you should be able to resolve the issue of $router being undefined in your Vue.js application.

In Nuxt.js with nuxt-i18n, we can call this.$router.push to navigate to a localized route.

To do this we can try the following.

Assuming we have a page called example.vue and we want to navigate to a localized route:

<template>
  <div>
    <button @click="navigateToLocalizedRoute">Go to Localized Route</button>
  </div>
</template>

<script>
export default {
  methods: {
    navigateToLocalizedRoute() {
      // Use this.$router.push to navigate to a localized route
      this.$router.push({ path: this.switchLocalePath('/localized-route') });
    }
  }
};
</script>

In this example, we define a method navigateToLocalizedRoute which will be triggered when the button is clicked.

Inside this method, we use this.$router.push to navigate to a localized route.

We use this.switchLocalePath('/localized-route') to get the localized path for the route /localized-route.

When calling this.$router.push, we pass an object with the path property set to the localized path.

Make sure we have properly configured the nuxt-i18n module in our Nuxt.js project, including setting up locales and defining localized routes in our nuxt.config.js file.

This method should work for navigating to any localized route within our application.

To make a computed property in Vue.js dependent on the current time, you can utilize a combination of JavaScript’s Date object and Vue’s reactivity system.

For example, we write

<template>
  <div>
    <p>The current time is: {{ currentTime }}</p>
    <p>The current hour is: {{ currentHour }}</p>
  </div>
</template>

<script>
export default {
  data() {
    return {
      currentTime: new Date()
    };
  },
  computed: {
    currentHour() {
      return this.currentTime.getHours();
    }
  },
  created() {
    // Update the currentTime property every second
    setInterval(() => {
      this.currentTime = new Date();
    }, 1000);
  }
};
</script>

In this example, we have a computed property currentHour that depends on the currentTime data property.

We initialize currentTime with the current date and time.

We update currentTime every second using setInterval to ensure that the computed property is re-evaluated as time progresses.

With this setup, currentHour will automatically update every second to reflect the current hour based on the system time.

We can similarly create computed properties dependent on other time-related aspects such as minutes, seconds, etc., by accessing different methods of the Date object.