Exploring TypeScript to get a ref with the Vue Composition API

The issue I'm facing is related to Vetur underlining 'null' in the following line:

const firstRef = ref<HTMLElement>(null)
<template>
  <input id="first" ref="firstRef">
  <button type="button" @click.prevent="focusFirst">Focus</button>
</template>

<script lang="ts">
import { defineComponent, ref } from "@vue/composition-api"
export default defineComponent({
  name: "Test",
  setup() {
    const firstRef = ref<HTMLElement>(null)
    const focusFirst = () => {
      const theField = firstRef.value
      theField.focus()
    }

    return { focusFirst }
  }
</script>

Answer №1

According to Vetur's feedback, converting a null type to an HTMLElement type is not possible. One way to resolve this issue is by initializing the reference like this:

const firstRef = ref<HTMLElement | null>(null)

Nevertheless, it is important to note that you will need to verify if firstRef is of type null before using it. You can also handle it in the following manner:

if (firstRef.value) {
  // perform operations with firstRef
  // TypeScript ensures it is an HTMLElement type at this point.
}

Answer №2

const elementReference = ref<HTMLElement | null>(null)

Attempting to access HTML properties, as well as Vue component methods and props, using the above code snippet can lead to errors. It is advisable to utilize the following syntax instead:

const myComponentRef = ref<InstanceType<typeof MyComponent>>()

Source: Enhancing typing for component references

Answer №3

One alternative method to consider is using optional chaining, which has been available since TypeScript 3.7:

firstRef.value?.focus()

This approach is suitable for TypeScript and will only run the command if firstRef.value is not null or undefined.

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

Handling events in a Vue application using JSX!

Is there a documentation section that explains the reasoning behind using camel case for click handlers, kebab case for inputs (and everything else) except for click where only onClick works? I've noticed that for common inputs both options work fine ...

Angular Typescript error: Trying to assign a value to 'someProperty' property of an undefined object

Within my Article class, I have a property called Image which is structured like this: export class Article { public image:Image; public images: Image[]; } If I decide to comment out this.article.image = new Image(); in the following way: constru ...

Avoid loading a header script while in development mode

Within my nuxt.config.js file, I have a script included in the html head configuration. export default { // Target: https://go.nuxtjs.dev/config-target target: 'static', // Global page headers: https://go.nuxtjs.dev/config-head head: { ...

Altering or including new space variables within a custom Chakra-ui theme

Looking to customize spacing variables in a Chakra UI theme? I have successfully implemented various extensions, but changes to spacing are not being applied. const config: ThemeConfig = { initialColorMode: 'light', useSystemColorMode: false ...

Is there a way to access the rootPath or other client-side information from the language server side?

I'm currently developing a language extension based on the example "language server" available at https://code.visualstudio.com/docs/extensions/example-language-server. In order to determine the current folder being used by vscode on the server side, ...

Odd behavior of escape characters in Typescript

Looking for help with a query similar to the one referenced here. I am new to TypeScript and front end development. Currently using an Angular form to collect user input, which may contain regex. For example: The input from the form, stored in this.expr ...

Arrange the list in the v-for loop in alphabetical order

My v-for is rendering the following Object/Data; export const data = [ {id: "1", albumname: "xx", artist: "xxxx", dateadded: "xxxx", route: "xxxx", songs: [{ song : 'check2.1', keysavail:[{key: "Am", route2: "/"}]}, { song : 'check2.2&apo ...

Using Jest: A guide to utilizing a mocked class instance

When working on my frontend React application, I decided to use the auth0-js library for authentication purposes. This library provides the WebAuth class which I utilize in my code by creating an instance like so: import { WebAuth } from 'auth0-js&ap ...

When moving the cursor quickly, a vertical line does not appear upon hover

I am facing an issue with the vue-chartJs library. When I move the cursor fast, the vertical line on hover does not show up. However, when I move the cursor slowly, it works perfectly. Can anyone offer assistance in solving this problem? onHover: functi ...

Ways to ensure that v-model does not become "true" or "false" in an input checkbox using Vue

I am currently working on a filter popup that includes a list of checkboxes. By default, some items should be selected and others not selected. I have connected these checkboxes to an object array using v-model. My issue is that when I deselect and select ...

Attempting to transform calc application into TypeScript, what data type should this function be?

Currently in the process of converting a calculator app to TypeScript. I've noticed that TypeScript is not prompting me to define the types for the three functions (handleClick, handleEqual, handleClear). Is specifying the type for the argument eno ...

The functionality of TypeScript's .entries() method is not available for the type 'DOMTokenList'

I'm currently working with a stack that includes Vue3, Vite, and TypeScript. I've encountered an issue related to DOMTokenList where I'm trying to utilize the .entries() method but TypeScript throws an error saying Property 'entries&apo ...

Is there a way to access data dynamically during rendering and display the outcome?

Upon rendering the object below, I am able to implement something similar to: <div v-for="(card, groupIndex) in cards" v-bind:key="card.id"> <div> {{cards[groupIndex].group.length}} </div> </div> This code snippet provides a cou ...

What is the best way to switch the direction of the arrows based on the sorting order?

Is there a way to dynamically change the direction of arrows based on sorting, similar to the example shown here? sortingPipe.ts: import { SprBitType } from '../spr-bit-type/sprBitType'; import { Pipe, PipeTransform } from '@angular/core& ...

When the Vue component is mounted through a v-if directive, the $el element is not present in

My popover component is designed to determine the position of its parent in the DOM and then attach itself to document.body while positioning itself absolutely. Everything works fine when I toggle the component visibility using v-show, but I encounter an ...

Encountering difficulties with a custom Firestore service when attempting to extend it after updating to Angular 9

My custom class that wraps Angular Firestore is designed to be extended and used throughout my application. However, after updating to Angular 9, this setup no longer functions properly. For the complete code snippet, visit . The abstract class wrapper: ...

Mastering the use of Quasar variables in your scss styles is crucial for optimizing your

I recently set up a project using Vue3 and Quasar by running vue add quasar. However, I am struggling to figure out how to utilize Quasar sass/scss variables. According to the documentation, I should use the following syntax: <style lang="scss&quo ...

Is it possible to execute a system command within an Ionic3 application?

How can I run a command from an app running in Chromium on Linux (or potentially Windows or Android in the future)? Why do you want to do this? To control, for example, some audio/TV equipment using cec-client. echo "tx 20:36" | cec-client RPI -s -d 4 ...

Deciding on the optimal times to implement data structure methods within Vue.js applications

Currently studying the Vue.js v2 documentation and I'm noticing a difference in how data is structured. When looking at the official documentation, they demonstrate creating data like this: var data = { a: 1 } var vm = new Vue({ el: '#example&a ...

Importing TypeScript modules dynamically can be achieved without the need for Promises

I find myself in a scenario where the dynamic nature of these commands is crucial to prevent excessive loading of unnecessary code when executing specific command-line tasks. if (diagnostics) { require('./lib/cli-commands/run-diagnostics').run ...