An idiomatic approach to check for the absence of null values

Recent JavaScript updates have introduced ?? and ?. to perform operations like locating the first non-nullish expression or referencing an object if it is not null.

[Additional Note: "nullish" indicates values that are either "null" or "undefined", as seen in the nullish coalescing operator].

Is there a more idiomatic approach to simply check for non-nullishness? For instance, determining whether to execute an onChange() handler only if the value is non-nullish. Like this:

someVal && onChange(someVal)

This method has its flaws since it would not work with falsy but still non-nullish values (such as 0 and '').

javascriptecmascript-6nullidiomsnullish-coalescing

Answer №1

One common way to handle this situation is by using an if statement with a null check:

if (someVal != null) onChange(someVal)

if (someVal != null) {
    onChange(someVal)
}

As of now, there isn't a dedicated operator for this specific scenario. While some have proposed extensions like the inverse null coalescing operator or changes to the pipeline operator proposal, none of these ideas have been implemented yet.

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

Enable the ability to upload multiple images on a single page using droparea.js

I am currently utilizing droparea js for uploading images. However, I have encountered an issue where if I try to upload an image in one of the upload menus, it ends up changing all four upload menus simultaneously. <div class="col-md-12"> ...

javascriptjqueryhtmlcss

No Results Returned by Sails Query Following count() Query

Upon execution, the following code returns empty results. Although the correct values are retrieved without the Count query, the final response remains empty. Could this issue be related to a race condition? module.exports = { getSites: function (req, res ...

javascriptmysqlnode.jssails.js

The loading of JavaScript takes place before the deployment of server-side images

Below is the Javascript code snippet: <%-- script to load the default image--%> <script type="text/javascript"><!-- window.addEventListener('load', function () { // Get the canvas element. var elem = document.g ...

c#javascriptasp.net

Fixed Header Table

Whenever I attempt to set the table header at a position other than 0, the body ends up scrolling above the header. Below is the code snippet showcasing the issue: .test { padding-top: 50px; } th { background-color: orange; position: sticky; to ...

javascripthtmlcssbootstrap-4flexbox

Passing an array from JavaScript to PHP using the $.post method

I am facing a challenge with my javascript array and ajax call setup. Here is the current situation: arr = [1, "string", 3] Below is my ajax call: $.post("./ajax_book_client.php", {'client_info[]': arr}, function(data) { ...

javascriptphpjqueryajax

Is the runTest.ts class in the vscode-test setup ever utilized in the project? Its purpose remains unclear even in the example project

Being a novice to Typescript, JavaScript, and VScode Extensions I have set up a vscode-test following the guidelines provided here: https://code.visualstudio.com/api/working-with-extensions/testing-extension#custom-setup-with-vscodetest Based on the hel ...

javascripttypescriptvisual-studio-codevscode-extensionsvscode-debugger

How come querySelector is effective while $() or document.getElementById do not respond properly with checkboxes?

Lynda.com's "Jquery Essential Training" course includes an assignment to create checkboxes that show and hide items with a specific data attribute based on whether they are checked or not. document.querySelector('#vitamincheck').addEventLis ...

javascriptjquerycheckboxselectors-api

Having trouble resolving a component from a component library while utilizing NPM link

My React application is set up with Create React App and a separate component library. I'm currently experimenting with using 'npm link' to test changes in the component library directly on my local machine. To achieve this, I first run &ap ...

javascriptnode.jsreactjsnpm

Send a file using XMLHttpRequest and include additional post data

I was looking on Google for information on how to send a post to an ashx page with both a file (for uploading) and some post parameters like the file's name. Does the XMLHttpRequest send(...) method accept both datafile and string in the same call? ...

javascriptasp.netajax

What is the best way to save characters from different languages into variables?

I created an application that reads words from a TXT file and stores them in a database. The issue arises when I encounter words from other languages that contain non-English characters, resulting in the following problem: Is it possible to store these ch ...

javascriptnode.js

What is causing my Vue leave transition to malfunction?

Currently, I am utilizing vee validate for my form validation. Specifically, I have implemented vue transition to handle the display of validation errors in the following manner: <input type="text" name="name" v-validate="'required'"> < ...

javascriptvue.jsvee-validate

What is the process for combining two distinct geometries with different materials into a single entity in three.js?

I created a 2D square line diagram followed by another square diagram with a sample image in the center position. However, one of them is visible while the other is hidden. I used two different geometries and materials - one with a line-based material se ...

javascriptcanvasthree.js

Displaying items in pairs in AngularJS with ng-repeat

The design I want to achieve is as follows: <div> <div class="row"> <div></div> <div></div> </div> <div class="row"> <div></div> <div></div> ...

javascriptangularjs

Is there a way to switch tabs through programming?

Is there a way to switch between tabs using jQuery or JavaScript when using the tabbed content from ? I have tried using $("tab1").click(); I have created a fiddle for this specific issue which can be found at: https://jsfiddle.net/6e3y9663/1/ ...

javascriptjquerytabs

Switching between two states of a single 'td' element within a column

I am trying to implement a feature where only specific elements in the fourth column of a four-column table toggle when clicked. For example, clicking on an element in the fifth row third column should toggle the corresponding element in the fifth row four ...

javascriptjqueryhtmlhtml-table

Avoiding the repetition of CSS animations during Gatsby page hydration

I am facing an issue in Gatsby where I have an element with an initial CSS animation. It works perfectly when the static site loads, but after hydration, it keeps repeating. Is there a way to prevent this from happening? Below is my styled components code ...

javascriptcssgatsbystyled-components

Executing $(this).parent().remove() triggers a full page reload

A unique feature of my webpage is that with just a simple click of a button, users have the ability to dynamically add an endless number of forms. Each form contains fields for user input and also includes a convenient delete button. var form = " Name ...

javascriptjqueryhtml

Setting up Firebase and Vue: Best practices for initializing Firebase and Vuefire

I am encountering an issue while setting up Vuefire and Firebase in my application. The error that I see in the console is: FirebaseError: Firebase: Firebase App named '[DEFAULT]' already exists (app/duplicate-app). at initializeApp (webpack ...

javascriptfirebasevue.jsvuefire

Assign characteristics to particular items within an array

When working with AngularJS/Javascript, I have an array of objects that each contain a date. My goal is to order these objects by date and then add an attribute to the last object that has a specific datetime. If there are two objects with the same date, t ...

javascriptangularjsarrays

Hold off until each loop retrieves data from the database

Currently, I am working on implementing a forEach method to retrieve data from a mongo database and store each piece of data in an array. My goal is to then log this array to the console once all the data has been collected. Despite my attempts with promis ...

javascriptnode.js