Setting a default value for a prop function in VueJS

How can a default function be set for a prop with the type of function?

props: {
    clickFunction: {
        type: 'Function'
        default: ????
    }
}

Answer №1

Affirmative:

Vue.component('bar', {
  template: '<div>{{ number }}</div>',
  props: {
    action: {
      type: Function,
      default: () => 1,
    },
  },
  data() {
    return { 
      number: this.action()
    }
  }
})

new Vue({
  el: '#application',
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script>
<div id="application">
  <bar></bar>
</div>

Answer №2

It is always a good practice to provide a default value that matches the specified type when setting props in your Vue components. This makes it much easier to understand and work with the code. For example, if you need a function that does nothing as a default value, you can define it like this:

props: {
  clickHandler: {
    type: Function,
    default: () => {}
  }
}

By using this.clickHandler() in your code, you can be confident that it will always be a function without needing defensive checks. Just be cautious not to confuse this approach with setting a default value for an Object prop, which would involve returning an empty object:

props: {
  someObject: {
    type: Object,
    default: () => ({})
  }
}

In Vue, it's important to return the default value for Object and Array props within a function to ensure they are unique for each component instance. Although this might not be necessary for Function props, clarity on this topic from the documentation would be helpful.

Answer №3

Here is a method that should function properly with Vue 2.0

parameters: {
    eventHandler: {
        format: 'Function'
        default(){
          return () => true
        }
    }
}

Answer №4

This approach may not be the most suitable for Vue. Why do you want to pass a reference to a function as a prop? Components can emit their own events that the parent can listen for.

If you need help with props types, check out: https://v2.vuejs.org/v2/guide/components-props.html

For information on custom events, visit: https://v2.vuejs.org/v2/guide/components-custom-events.html#Event-Names

Edit I realize that my initial answer was incorrect and did not address the question directly. To answer simply: yes, there are various ways to set a default function for a prop with a function type (refer to other answers).

I will stop here on the topic of patterns and use-cases being off-topic (although someone provided an interesting insight in response to my answer).

Similar questions

If you have not found the answer to your question or you are interested in this topic, then look at other similar questions below or use the search

Change the size of window using jQuery

I have implemented a tooltip that can appear in two positions: top and bottom. I am trying to achieve this using jQuery resize function. The issue I am facing is that when the user resizes their browser window to less than 768px, the tooltip should appea ...

403 Malicious Path Middleware Error in Express.js

Encountering an error when sending a post request to my server, but only on the production server - whereas the staging server is functioning properly. Both servers are hosted on AWS Ubuntu instances. Investigating the stack trace, it appears that the err ...

Retrieve JSON data with Bootstrap Typeahead for both ID and Value

To enable autocomplete for the typeahead feature, I want it to work specifically with the name field. When an item is clicked, I need it to collect the corresponding id value. $('.autocomplete').typeahead({ source: function (query, process) ...

launch a website independently of the original source code

I recently completed a website project using PHP. I'm interested in deploying it without sharing the source code. Is this something that can be done with PHP? Is there a way to convert my website's code into an intermediate form before deploymen ...

Challenges with creating a contact form using bootstrap modal

I'm facing an issue with a bootstrap modal contact form. It works fine on all browsers except for iPad/Safari. Can anyone help me figure out what's wrong? On iPad, the modal is positioned to the right and down the page instead of in the cente ...

New post: "Exploring the latest features in Angular

Looking for help with integrating Angular and SpringREST to fetch data from the backend? Here's my situation: I need to retrieve a JSON string from the backend using a POST request, send it to my site's hosted link, and display it on the user int ...

Is it possible to identify in Next.js whether scrollRestoration was triggered, or if the back button was pressed?

I've been utilizing the scrollRestoration functionality within Next.js to save and restore the page position whenever a user navigates using the back button. However, I've encountered an issue with it not restoring the horizontal scroll position ...

Obtain the current URL in a Node.js configuration file

In my application using the express framework, I have the following code in my app.js file: var express = require('express'); var app = module.exports = express(); var config = require('./config.js')(app, express); // Including ...

One way to reset a modal to have a false value after it has been opened once is

I have a component that loads a modal with instructions every time it is loaded, but I only want it to happen once. If the user presses F5, I don't want the modal to show again unless they trigger it with a button. How can I achieve this? Do I need a ...

Optimizing the performance of J2EE web applications

I am currently working on enhancing the performance of my web application. The application is java-based and is hosted on an Amazon cloud server with JBoss and Apache. One particular page in the application is experiencing a slow loading time of 13-14 sec ...

Issues with React Native: Struggling to iterate through an array and show it with an image URL stored

Just diving into React and I'm facing a challenge with my code. I have an array stored in my .state that I want to loop through and display the images. (I'm using 'Image' and a Card object from https://github.com/lhandel/react-native-ca ...

What is the process for modifying a Gist on GitHub?

Trying to update my Gist from another website using my gist token has been unsuccessful. Retrieving a gist with GET was successful, but updating it with PATCH is not working. I don't believe authentication is the issue since retrieving the gist displ ...

The Vue route parameters are not recognized within the function type

Seeking assistance on extracting parameters from my route in a vue page, I have the following implementation: <script lang="ts"> import { defineComponent } from 'vue'; import { useRoute } from 'vue-router'; export ...

Using AngularJS to create nested ng-repeat loops with conditional statements

Hey there, I'm facing an issue where multiple ng-repeat directives are nested like this: <form ng-repeat="pt in prolist"> Frequency <input type="checkbox" ng-model="pt.req" /> <div ng-repeat="disc in prolist"> ------ </d ...

Close pop-up upon successful AJAX response in ASP.NET MVC

I have a modal in my view that allows me to create a new record in the database. The view for this functionality is contained within a partial view. Below is the code for the view: <script src="~/Scripts/jquery-3.1.1.js"></script> To han ...

Tips for formatting numerical output in EJS by rounding the value

I am displaying a value in EJS and I am looking to format it to show fewer decimal places. This is related to the EJS engine on the frontend. Value displayed: 4.333333333333333 I want it to be displayed like this: 4.3 The EJS code snippet used: <p cl ...

Incorporating a parameter into a <div> only when the parameter holds a value

Being new to web development, I have a rather basic query. If the datainfo prop variable is not empty, I'd like to include a data attribute in the div tag. <div style={{height: props.height - handleHeight()}} data={datainfo ? datainfo : ""}> C ...

bringing in documents from a shared repository

Exploring the folder structure below: MainFolder ├──sourceFolder │ └──assetsFolder │ ├──GlobalStyles.js │ ├──colors.js │ ├──images.js │ ├──someOtherFile.js │ └──package.json <-- ...

Encountered an issue while trying to register a service worker: "[ERROR] Cannot import statement outside

With the utilization of register-service-worker, the boilerplate for registerServiceWorker remained untouched. /* eslint-disable no-console */ import { register } from 'register-service-worker'; if (process.env.NODE_ENV === 'production&ap ...

Error message: A boolean type cannot be used as a function in the fullcalendar ajax call

I have successfully implemented a fullcalendar into my app and have added a method to filter results by user: function filterEventsByProvider(selected_provider) { $('#calendar').fullCalendar('removeEvents'); $('#calendar&a ...