optional chaining operator - Brave Search

How does the JavaScript optional chaining(?.) operator works?

stackoverflow.com › questions › 64573952 › how-does-the-javascript-optional-chaining-operator-works

Its called "optional chaining" operator. It moves from left to right. if it sees ?. it checks the left value if its undefined or null. if yes, it returns undefined and stops moving to the right. that means if b is already undefined it wont check the values on the right side

Answer from Ilijanovic on Stack Overflow

developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Operators › Optional_chaining

Optional chaining (?.) - JavaScript | MDN

The optional chaining (?.) operator accesses an object's property or calls a function. If the object accessed or function called using this operator is undefined or null, the expression short circuits and evaluates to undefined instead of throwing an error.

forum.freecodecamp.org › javascript

What Is the Optional Chaining Operator, and How Does It Work?

April 8, 2025 - TLDR: Optional Chaining Operator is for objects, not properties? https://www.w3schools.com/jS/js_2020.asp " The Optional Chaining Operator returns undefined if an object is undefined or null (instead of throwing an er…

Discussions

[AskJS] Over-using optional chaining. Is this pattern common?

Optional chaining is great. I find it however quite frustrating that TC39 included the "optional call" syntax that you're illustrating. THAT is a terrible feature that should be avoided, IMO. Besides it looking weird (like a typo), one reason I dislike it so much is that it seems (to the reader) like it's checking if the function can be called, and only calling it if safe to do so. But that's not what it's doing. It's only checking if the callee is not-nullish. var isThisAFunction1 = null; var isThisAFunction2 = "oops"; // later isThisAFunction1?.(); // safely a no-op isThisAFunction2?.(); // Exception! More on reddit.com

r/javascript

25

5

January 18, 2021

ecmascript next - How does the JavaScript optional chaining(?.) operator works? - Stack Overflow

I was looking into the new JS optional chaining?. operator. It helps us from getting errors like this, TypeError: Cannot read property ‘x’ of undefined You can write const obj = {a: 1}; console.lo... More on stackoverflow.com

stackoverflow.com

Using optional chaining operator for object property access

TypeScript 3.7 now supports the optional chaining operator. Hence, you can write code such as: const value = a?.b?.c; I.e., you can use this operator to access properties of an object, where the o... More on stackoverflow.com

stackoverflow.com

[AskJS] Is it a problem if the code base is filled with optional chaining?

A mantra in the Zig community that is applicable here: "Handled errors are better than exceptions, but exceptions are better than bugs" More on reddit.com

r/javascript

43

15

July 17, 2024

Videos

Master the Optional Chaining Operator in JavaScript|React|Nextjs ...

Optional Chaining In JavaScript: Awesome. - YouTube

January 30, 2024

Optional Chaining (?.) In 2 Minutes - ES2020 - YouTube

August 17, 2023

Optional Chaining Operator (?.) in JavaScript - YouTube

How to Use Optional Chaining (?.) in JavaScript - YouTube

January 27, 2021

geeksforgeeks.org › javascript › javascript-optional-chaining

JavaScript Optional Chaining - GeeksforGeeks

Optional Chaining (ES2020) safely accesses properties or calls functions on null or undefined values.

Published January 12, 2026

reddit.com › r/javascript › [askjs] over-using optional chaining. is this pattern common?

r/javascript on Reddit: [AskJS] Over-using optional chaining. Is this pattern common?

January 18, 2021 -

Hi everyone!

I love optional chaining, i really do, but there are some cases where using this syntax damages the readability of the code. One of those cases is the following

function optionalFunction(){     
    console.log("works"); 
}  
// optionalFunction = undefined;  

optionalFunction?.();

While i understand this approach, i find it optionalFunction?.() harder to read as opposed to this

function optionalFunction(){     
    console.log("works"); 
}  
// optionalFunction = undefined;  

if(optionalFunction != undefined){     
    optionalFunction(); 
}

I think i'd rather have a more readable and stronger check than ES6 magic when checking if an optional function is defined.

I believe that optional chaining fixes the problem of checking if a property of an object exists, and if exists, then get the value or keep going deeper in the object structure. But this syntax just looks weird for calling functions, it looks a lot like those "one line cleverness" code that sometimes people encounter.

What are your thoughts about this?

Optional chaining is great. I find it however quite frustrating that TC39 included the "optional call" syntax that you're illustrating. THAT is a terrible feature that should be avoided, IMO. Besides it looking weird (like a typo), one reason I dislike it so much is that it seems (to the reader) like it's checking if the function can be called, and only calling it if safe to do so. But that's not what it's doing. It's only checking if the callee is not-nullish. var isThisAFunction1 = null; var isThisAFunction2 = "oops"; // later isThisAFunction1?.(); // safely a no-op isThisAFunction2?.(); // Exception!

I haven't really started using optional chaining yet, but the idiom I mostly encounter for optional callbacks etc. is onEnd && onEnd() I would personally only use optional chaining for "deeply" nested properties. const city = user.?address?.city || defaultCity

stackoverflow.com › questions › 64573952 › how-does-the-javascript-optional-chaining-operator-works

ecmascript next - How does the JavaScript optional chaining(?.) operator works? - Stack Overflow

Its called "optional chaining" operator. It moves from left to right. if it sees ?. it checks the left value if its undefined or null. if yes, it returns undefined and stops moving to the right. that means if b is already undefined it wont check the values on the right side

In the example below, obj has only one key a.

const obj = {a: 1};
console.log(obj?.b);

In the above code snippet, there is no property b in object because of which it is printing undefined.

console.log(obj.b.c.d?.e);
console.log(obj.b?.c.d?.e);

Even in the code above, the same thing is happening where the object is not having key b hence it is printing undefined. So if you want to see that obj.b.c is undefined then the object should look the one below:

obj: {
    b: '123'
}

JavaScript.info

javascript.info › tutorial › the javascript language › objects: the basics

Optional chaining '?.'

April 14, 2022 - There’s a little better way to write it, using the && operator: let user = {}; // user has no address alert( user.address && user.address.street && user.address.street.name ); // undefined (no error) AND’ing the whole path to the property ensures that all components exist (if not, the evaluation stops), but also isnt ideal. As you can see, property names are still duplicated in the code. E.g. in the code above, user.address appears three times. That’s why the optional chaining ?.

Find elsewhere

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typescriptlang.org › docs › handbook › release-notes › typescript-3-7.html

TypeScript: Documentation - TypeScript 3.7

At its core, optional chaining lets us write code where TypeScript can immediately stop running some expressions if we run into a null or undefined. The star of the show in optional chaining is the new ?. operator for optional property accesses.

stackoverflow.com › questions › 58780817 › using-optional-chaining-operator-for-object-property-access

Using optional chaining operator for object property access

When accessing a property using bracket notation and optional chaining, you need to use a dot in addition to the brackets:

const value = a?.[b]?.c;

This is the syntax that was adopted by the TC39 proposal, because otherwise it's hard for the parser to figure out if this ? is part of a ternary expression or part of optional chaining.

The way I think about it: the symbol for optional chaining isn't ?, it's ?.. If you're doing optional chaining, you'll always be using both characters.

The Optional Chaining operator is `?.`

Here are some examples for nullable property and function handling.

const example = {a: ["first", {b:3}, false]}

// Properties
example?.a  // ["first", {b:3}, false]
example?.b  // undefined

// Dynamic properties ?.[]
example?.a?.[0]     // "first"
example?.a?.[1]?.a  // undefined
example?.a?.[1]?.b  // 3

// Functions ?.()
null?.()                // undefined
validFunction?.()       // result
(() => {return 1})?.()  // 1

Bonus: Default values

?? (Nullish Coalescing) can be used to set a default value if undefined or null.

const notNull = possiblyNull ?? defaultValue
const alsoNotNull = a?.b?.c ?? possiblyNullFallback ?? defaultValue

docs.swift.org › swift-book › documentation › the-swift-programming-language › optionalchaining

Optional Chaining - Documentation | Swift.org

This document is made available under a Creative Commons Attribution 4.0 International (CC BY 4.0) License · Swift and the Swift logo are trademarks of Apple Inc

dev.to › tusharshahi › cost-of-unnecessary-optional-chaining-and-nullish-coalescing-operator-3h09

Cost of unnecessary Optional Chaining (and Nullish coalescing operator) - DEV Community

April 6, 2024 - The first one is optional chaining and the other one is the nullish coalescing operator.

reddit.com › r/javascript › [askjs] is it a problem if the code base is filled with optional chaining?

r/javascript on Reddit: [AskJS] Is it a problem if the code base is filled with optional chaining?

July 17, 2024 -

Jumping into a new code base and it seems like optional chaining is used EVERYWHERE.

data?.recipes?.items
label?.title?.toUpperCase();
etc.

It almost seems like any time there is chaining on an object, it always includes the ?.

Would you consider this an anti-pattern? Do you see any issues with this or concerns?

A mantra in the Zig community that is applicable here: "Handled errors are better than exceptions, but exceptions are better than bugs"

Conditional access itself is not bad, no. What's bad is that what you're showing here implies that every piece of data here is basically "this could exist, or it could not, it's a suprise teehee!"

developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Operators › Nullish_coalescing

Nullish coalescing operator (??) - JavaScript | MDN

The nullish coalescing operator treats undefined and null as specific values. So does the optional chaining operator (?.), which is useful to access a property of an object which may be null or undefined.

forums.swift.org › using swift

Optional chaining with operators - Using Swift - Swift Forums

February 2, 2022 - Optional chaining can be used with methods, mutating methods, and assignment operators: var x: Int? = 0 x?.addingReportingOverflow(1) x?.negate() x? += 2 However, it currently cannot be used with non-assignment operators: x? + 3 // error: Value ...

w3schools.com › js › js_2020.asp

Optional chaining not only works on object properties, but also on function calls and arrays. The Logical AND Assignment Operator is used between two values.

typescriptlang.org › play › 3-7 › syntax-and-messaging › optional-chaining.ts

TypeScript: Playground Example - Optional Chaining

const artistBio = album?.artist?.bio; ... values (e.g. an empty string, 0, NaN, and, well, false). Optional chaining will only take null or undefined as a signal to stop and return an undefined. Optional Element Access Property access is via the . operator, the optional chaining ...

v8.dev › features › optional-chaining

Optional chaining · V8

August 27, 2019 - What happens when db, user, or name is undefined or null? With the optional chaining operator, JavaScript initializes nameLength to undefined instead of throwing an error.

mariusschulz.com › blog › optional-chaining-the-operator-in-typescript

Optional Chaining: The ?. Operator in TypeScript — Marius Schulz

September 11, 2021 - TypeScript 3.7 added support for ... use this operator to descend into an object whose properties potentially hold the values null or undefined without writing any null checks for intermediate properties....

groups.google.com › a › chromium.org › g › chromium-dev › c › DHLSm05HHlo

Allow optional chaining operator in Chromium Web code

September 28, 2022 - Looking at https://chromium.googlesource.com/chromium/src/+/HEAD/styleguide/web/es.md it seems that the optional chaining operator (?.) is currently banned.

dev.to › macsikora › what-is-wrong-with-optional-chaining-and-how-to-fix-it-3nno

What is wrong with optional chaining and how to fix it - DEV Community

May 1, 2020 - Edit: There is nothing wrong with optional chaining, the feature is related to idiomatic absence value in JS, and it is "null | undefined". The operator tries to address issues of previously used &&. This article tries to make a point that JS ...

community.coda.io › suggestion box

Optional chaining operator - Suggestion Box - Coda Maker Community

January 6, 2021 - Would be nice to have an optional chaining operator (similar to JavaScript’s ?., see Optional chaining (?.) - JavaScript | MDN), essentially that navigates the same as the regular . operator, with the exception that it short-circuits and returns ...