Category: Vue

No, directly pushing items into an array using state.array.push() inside a Vuex mutation won’t trigger reactivity in Vue.js.

This is because Vue cannot detect mutations to arrays when we directly modify them, such as using methods like push(), pop(), splice(), etc.

To maintain reactivity, we should use Vue’s set or splice methods, or if we’re using Vuex, we should return a new array with the updated values. Here’s how we can do it:

// In our Vuex store
mutations: {
  addItem(state, item) {
    state.array = [...state.array, item]; // This maintains reactivity by returning a new array with the added item
  }
}

Or using Vue’s set method:

// In our Vuex store
mutations: {
  addItem(state, item) {
    Vue.set(state.array, state.array.length, item);
  }
}

Using Vue.set or returning a new array ensures that Vue can detect the change and trigger reactivity appropriately. This is important especially if state.array is being watched or bound in any Vue components.

We can show a confirmation dialog before route changes in a Vue.js application by leveraging Vue Router navigation guards.

Specifically, we can use the beforeRouteLeave guard to intercept route changes and display a confirmation dialog. Here’s a basic example of how to implement this:

// main.js or our Vue entry file

import Vue from 'vue';
import VueRouter from 'vue-router';
import App from './App.vue';

Vue.use(VueRouter);

const routes = [
  // Our routes here
];

const router = new VueRouter({
  routes
});

router.beforeEach((to, from, next) => {
  // Check if the component has a beforeRouteLeave hook
  if (from.meta.confirmation && typeof from.meta.confirmation === 'function') {
    // Call the confirmation function passing the next() callback
    from.meta.confirmation(next);
  } else {
    // If there's no confirmation function, proceed to the next route
    next();
  }
});

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

Then, in our component where we want to show the confirmation dialog before route change, we can define the beforeRouteLeave hook along with the confirmation logic. Here’s an example:

// YourComponent.vue

export default {
  data() {
    return {
      confirmDialog: false // Whether to show the confirmation dialog or not
    };
  },
  beforeRouteLeave(to, from, next) {
    // If confirmation is required, set confirmDialog to true
    if (/* Our condition for showing the confirmation dialog */) {
      this.confirmDialog = true;
      
      // Define the confirmation logic
      this.$nextTick(() => {
        // Display confirmation dialog using our preferred UI library/modal
        // Example with native confirm dialog
        if (confirm("Are you sure you want to leave this page?")) {
          // If confirmed, proceed to the next route
          next();
        } else {
          // If not confirmed, stay on the current route
          next(false);
        }
      });
    } else {
      // If confirmation is not required, proceed to the next route
      next();
    }
  }
};

This way, before leaving the current route, the beforeRouteLeave hook will be triggered, and if the condition for showing the confirmation dialog is met, it will display the dialog and wait for user confirmation before proceeding to the next route.

To call preventDefault() on form submission with Vue.js, we can use the .prevent event modifier in the form submission event handler.

This modifier tells Vue.js to automatically call event.preventDefault() when handling the event.

To do this we write:

<template>
  <form @submit.prevent="submitForm">
    <input type="text" v-model="username" placeholder="Username">
    <input type="password" v-model="password" placeholder="Password">
    <button type="submit">Submit</button>
  </form>
</template>

<script>
export default {
  data() {
    return {
      username: '',
      password: ''
    };
  },
  methods: {
    submitForm(event) {
      // Our form submission logic here
    }
  }
};
</script>

The @submit.prevent directive listens for the submit event on the form and calls event.preventDefault() internally to prevent the default form submission behavior.

When the form is submitted, the submitForm method is called.

Inside the submitForm method, we can implement our custom form submission logic.

Vue.js automatically passes the event object to the event handler, so we can access it and call event.preventDefault() if needed.

Using @submit.prevent is a convenient way to prevent the default form submission behavior while handling form submissions with Vue.js.

If you’re using Vue.js with the Bulma CSS framework and you find that all columns are displaying on one line, it’s likely because you haven’t wrapped your columns in a .columns container.

In Bulma, columns should be wrapped within a .columns container to properly align them.

For instance we write

<template>
  <div>
    <div class="columns">
      <div class="column">
        <!-- Content for the first column -->
      </div>
      <div class="column">
        <!-- Content for the second column -->
      </div>
      <!-- Add more columns as needed -->
    </div>
  </div>
</template>

<script>
export default {
  // Your Vue component logic
};
</script>

<style lang="scss" scoped>
/* Add any custom styles here */
</style>

In this example we wrap our columns within a div with the class .columns.

Each column is wrapped within a div with the class .column.

Ensure that you have properly included the Bulma CSS in your project for the column layout to work correctly. You can include it via a CDN link, npm package, or any other method as per your project setup.

Make sure to replace the placeholder content in the columns with your actual content. This structure should ensure that your columns display correctly and are not all on one line.

In Vuetify, we can access data in form rules by using the v-model directive to bind form inputs to data properties and then referencing those properties in your form rules.

For example, we write

<template>
  <v-form @submit.prevent="submitForm">
    <v-text-field v-model="username" label="Username" required></v-text-field>
    <v-text-field v-model="password" label="Password" required></v-text-field>
    <v-btn type="submit" :disabled="!validForm">Submit</v-btn>
  </v-form>
</template>

<script>
export default {
  data() {
    return {
      username: '',
      password: ''
    };
  },
  computed: {
    validForm() {
      return this.username !== '' && this.password !== '';
    }
  },
  methods: {
    submitForm() {
      // Form submission logic
    }
  }
};
</script>

In this example we have two text fields for username and password, each bound to username and password data properties using v-model.

We use the required attribute in the text fields to ensure they are not empty.

We have a computed property called validForm which returns true if both the username and password fields have values, and false otherwise.

The “Submit” button is disabled when the validForm computed property returns false, preventing form submission until both fields are filled.

The form submission logic is handled by the submitForm method, which we can implement as needed.

We can add more complex form rules by using additional computed properties or methods that reference other data properties or perform custom validation logic based on our requirements.