Should one create code to transfer data to a child component in vue.js?

I have encountered an issue while using vue.js with defineComponent.

My goal is to obtain data and pass it to child components, but unfortunately the data turns out to be undefined.

parent

<template>
  <Child :data="user"/>
  <div>{{ user.name }}</div> <!-- It works here -->
</template>

export default defineComponent({
  setup() {
    const user = ref({});
    const getData = () => {
      // takes 3 seconds
      user.value = data;
    }
    return {user}
  }
})

child

<template>
  <div>{{ user.name }}</div> <!-- TypeError Cannot read properties of undefined -->
</template>

export default defineComponent({
  props: {
    data: { type: Object },
  },
  setup(props) {
    const user = ref(props.data);
    return {user}
  }
})

After implementing watch in the child component, the issue was resolved. Is this the correct approach to solve such problems?

child

export default defineComponent({
  props: {
    data: { type: Object },
  },
  setup(props) {
    const user = ref({});
    watch(props, (n, o) => user.value = props.data)
  }
})

Answer №1

When dealing with asynchronous data in your Vue component, it's important to handle empty props effectively to prevent errors. If you pass an empty object as a prop, like in the case of {}, accessing properties such as {}.name will return undefined without causing any issues.

There are different approaches you can take to manage empty props within your components:

  1. Wait to render the child component until the full data is available:
<Child v-if="user" :data="user" />

This method ensures that the Child component code is only executed when the required data is present.

  1. Handle the absence of data directly within the Child component:
<template>
  <div v-if="!data">Loading...</div>
  <div v-else>
    {{ data.name }}
  </div>
</template>

This approach allows you to display a loading message or alternative content when the data is missing.


It's worth noting that there's no need to duplicate the props.data into a ref within your component unless you intend to modify it. In such cases, use a watcher to ensure that changes to the prop are reflected in the inner user ref and maintain synchronization between the Child component's data and the original data prop.

Answer №2

For your specific scenario, the current approach is appropriate since you only have a 3-second window to retrieve data.

The challenge arises when the child component attempts to access the data before it becomes available. This occurs because the parent component's getData() function takes 3 seconds to execute, leaving the user object empty during this period. Consequently, when the child component is initialized, it tries to reference the user object prematurely, resulting in an error being generated.

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

What is the best way to output the leaf nodes from an array of object lists in TypeScript?

Having trouble with TypeScript, specifically working with arrays and filtering out leaf nodes. I want to print only the leaf nodes in the array, resulting in ['002', '004', '007']. Can someone please assist me? Excited to lear ...

Why isn't the angularjs directive setting a value for a specific scope?

This is an example of HTML code: <div ng-controller="main"> <div ng-show="showhide">welcome</div> <div my-directive>click</div> <div ng-click="submit()">submit</div> </div> Here ...

React Typescript: Error - Attempting to access properties of undefined while attempting to read 'map'

I've been attempting to display user data on a card component fetched from jsonplaceholder using axios. However, I keep encountering an error message: "TypeError: Cannot read properties of undefined (reading 'map')". Despite trying various s ...

Restore the images to their original state once the user scrolls back to the top

I have implemented 2 static images with fixed positions at the edges of the screen (one on the right and one on the left). The logic I want to achieve is that when a user scrolls more than 100 pixels from the top, these edge images should move back by 50 p ...

Exploring the functionality of AngularJS routing on a webpage

Testing the routing functionality of AngularJS while creating a web page. The index.html will contain links to Home, Courses, and Students. Clicking on each link will load its respective HTML using AngularJS routing. The student information is stored in ...

I am experiencing issues with editing the text field in React Tab as it keeps getting out of focus

https://i.sstatic.net/AUxlN.png Whenever I try to type, the text box loses focus and only allows me to type one letter at a time. Below is the code snippet that I am using: <TabPanel value={value} index={0}> {[...Array(commentCount)].map((item, in ...

Sending an image file using AJAX and jQuery

I am currently using Mustache JS to generate a template called 'addUser1' for display purposes. However, when I execute this code, only the image location is being sent to the server, not the actual image itself. What could be causing this issue? ...

What might be causing the issue with my ajax request to the PHP file within the data parameter?

Although I am successfully getting my php value into a JavaScript variable, it seems like my script.js file is unable to find it. For the sake of brevity, some files have been omitted in this question. The main issue is that the script.js file retrieves th ...

Show graph post form submission using AJAX

Looking to generate a detailed report with data pulled from the server, including a chart. I've been attempting to use $.getJSON to send the JSON data after the form is submitted, but running into issues trying to echo out $_GET[rep] to verify I' ...

Using the updated values from a range slider in JavaScript: A step-by-step guide

In the scenario where a slider has been created and the value is being changed using a mouse, the challenge is how to utilize these values as variables in the global scope. It is important that this variable updates to the new value when the slider is ad ...

What might be causing me to only view a black background while using ThreeJS in conjunction with VueJS?

Hey there! I recently incorporated a new component into my project that utilizes ThreeJS. My intention is to create a visually appealing scene with a light background and two boxes. However, despite my efforts to render the boxes, all I see is a black back ...

clicking on a link with the symbol "#" in the href attribute in Firefox prevents the setter

Good morning everyone, It's early Monday morning and I'm having trouble understanding why this particular line works in Internet Explorer but not in Firefox. <a class="button" href="#" onclick="setMaintenanceMode(false);">disable</a> ...

Designing a slider to display a collection of images

I am currently working on a slider project using HTML, javascript, and CSS. I'm facing an issue where only the first two images (li) are being displayed and it's not transitioning to the other (li) elements. Below is the HTML code snippet: <se ...

Incorporating EJS Template Body Parameters into AWS Lambda's Handler.js Using Serverless.yml

I have a scenario where I am trying to embed an EJS template named 'ui.ejs' into my handler.js file. The goal is to extract URL query parameters, then pass them to a function called 'ui.js' to retrieve data, which will then be displayed ...

Ways to extract Document ID from a Firestore database collection

Currently, I am in the process of developing a mobile app using React Native and Firebase. My main focus right now is on accessing document data without explicitly specifying the ID, unlike the method shown below: const docRef = db.collection('vehicle ...

Creating a "return" button for an editing form in AngularJS Datatables with the help of a form directive

Using AngularJS Datatables, I implemented a grid with additional "edit" and "delete" buttons in the last column. How is the grid/table rendered? HTML <!-- Required CSS and JS --> <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/li ...

Transforming substantial quantities of data into a string array in JavaScript

I have around 2000 items of data that I work with on a regular basis in Visual Studio Code. Is there a way to convert this data into a string array without having to manually add quotes around each item using JavaScript? var array = [ a2kjda a2dkj ...

Warning issued by npm during compilation: The template string expression is unexpected as there should be no curly braces in the

Getting an npm warning during compiling (Unexpected template string expression no-template-curly-in-string) import React from 'react'; const Card = ({name, email, id }) => { return ( <div className='tc bg-light-green dib b ...

Is there a way for me to make my Note element automatically update whenever I modify its text content?

Feeling a bit stuck with my project, especially this part. I'm currently using React to develop a notes application, and I'm having trouble updating the note when changing the text within the modal popup. The commented sections are where I need h ...

What is the best way to bring my file into app.js using JavaScript?

I've been attempting to include a JavaScript file into app.js within the create-react-app package. I tried the following code to import my file: Just a heads up: my file is located in a folder called components within the Navigation folder. import s ...