MDN Web Docs
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.
JavaScript.info
javascript.info › tutorial › the javascript language › objects: the basics
Optional chaining '?.'
E.g. in user?.address.street.name the ?. allows user to safely be null/undefined (and returns undefined in that case), but that’s only for user. Further properties are accessed in a regular way. If we want some of them to be optional, then we’ll need to replace more .
freeCodeCamp
forum.freecodecamp.org › javascript
What Is the Optional Chaining Operator, and How Does It Work? - JavaScript - The freeCodeCamp Forum
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…
W3Schools
w3schools.io › javascript › es11-optional-chaining
ES2020(ES11) - Javascript Optional Chaining Operator - w3schools
This tutorial covers the latest javascript features, Optional Chaining Operator released in 2020. ES11 or ES2020 or EcmaScript2020 .
GeeksforGeeks
geeksforgeeks.org › javascript › javascript-optional-chaining
JavaScript Optional Chaining - GeeksforGeeks
The Optional Chaining Operator allows a developer to handle many of those cases without repeating themselves by assigning intermediate results in temporary variables: ... Note: If this code gives any error try to run it on online JavaScript editor.
Published June 22, 2020
W3Schools
w3schools.com › js › js_2020.asp
JavaScript 2020
The Optional Chaining Operator returns undefined if an object property is undefined or null (instead of throwing an error).
JavaScript Tutorial
javascripttutorial.net › home › javascript tutorial › javascript optional chaining operator
JavaScript Optional Chaining Operator (?.)
December 17, 2023 - In this tutorial, you'll learn about the optional chaining operator (?.) that simplifies the way to access values through connected objects
freeCodeCamp
freecodecamp.org › news › optional-chaining-javascript
Optional Chaining in JavaScript – Explained with Examples
February 13, 2024 - The optional chaining operator (?.) allows you to access properties or methods without the need for explicit null or undefined checks. If any intermediate property in the chain is null or undefined, the expression short-circuits, and the result ...
freeCodeCamp
freecodecamp.org › news › javascript-optional-chaining
How to Use Optional Chaining in JavaScript
February 7, 2022 - The optional chaining operator ?. takes the reference to its left and checks if it is undefined or null. If the reference is either of these nullish values, the checks will stop and return undefined.
YouTube
youtube.com › dcode
Optional Chaining Operator (?.) in JavaScript - YouTube
The optional chaining operator in JavaScript is convenient as it allows the developer to specify an object's property as being optional, and only return a va...
Published April 6, 2021 Views 23K
W3Schools
w3schools.com › nodejs › nodejs_es6.asp
Node.js ES6+ Features
Modern JavaScript introduces syntax to safely access nested properties and provide fallback values. Optional chaining lets you access deeply nested object properties without worrying about null or undefined values in the chain.
TutorialsPoint
tutorialspoint.com › javascript › javascript_optional_chaining.htm
JavaScript - Optional Chaining
When any object property doesn't exist, the optional chain stops the code execution and returns undefined. If you use the JavaScript nullish coalescing operator with it, you can return the default value when the object property doesn't exist.
Codecademy
codecademy.com › docs › javascript › optional chaining
JavaScript | Optional Chaining | Codecademy
August 7, 2025 - The optional chaining operator allows safe access to nested object properties or methods without having to explicitly check if intermediate properties exist.
Top answer 1 of 5
589
You need to put a . after the ? to use optional chaining:
myArray.filter(x => x.testKey === myTestKey)?.[0]
Playground link
Using just the ? alone makes the compiler think you're trying to use the conditional operator (and then it throws an error since it doesn't see a : later)
Optional chaining isn't just a TypeScript thing - it is a finished proposal in plain JavaScript too.
It can be used with bracket notation like above, but it can also be used with dot notation property access:
const obj = {
prop2: {
nested2: 'val2'
}
};
console.log(
obj.prop1?.nested1,
obj.prop2?.nested2
);And with function calls:
const obj = {
fn2: () => console.log('fn2 running')
};
obj.fn1?.();
obj.fn2?.(); 2 of 5
50
Just found it after a little searching on the what's new page on official documentation
The right way to do it with array is to add . after ?
so it'll be like
myArray.filter(x => x.testKey === myTestKey)?.[0] // in case of object
x?.() // in case of function
I'll like to throw some more light on what exactly happens with my above question case.
myArray.filter(x => x.testKey === myTestKey)?[0]
Transpiles to
const result = myArray.filter(x => x.testKey === myTestKey) ? [0] : ;
Due to which it throws the error since there's something missing after : and you probably don't want your code to be transpilled to this.
Thanks to Certain Performance's answer I learned new things about typescript especially the tool https://www.typescriptlang.org/play/index.html .
Dmitri Pavlutin
dmitripavlutin.com › javascript-optional-chaining
How to Use JavaScript Optional Chaining
Optional chaining accesses properties from deep of nested objects without prop existence verification and intermediate variables boilerplates.
W3Schools
w3schools.com › jsref › jsref_oper_optional.asp
JavaScript Optional Chaning Operator
Optional Chaning is a JavaScript 2020 feature. ES 2020 is supported in all modern browsers since September 2020: ... If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail: sales@w3schools.com
V8
v8.dev › features › optional-chaining
Optional chaining · V8
We could change name?.length to name.length. Then, if name were an empty string, we would still get the correct 0 length. That is because the empty string is a falsy value: it behaves like false in an if clause. The optional chaining operator fixes this common source of bugs.
daily.dev
daily.dev › home › blog › webdev › optional chaining in javascript - what is it and how to use it?
Optional Chaining In JavaScript - What Is It And How To Use It?
November 1, 2021 - The optional chaining feature is similar to the `.` chaining operator. The only difference is that it returns the value of undefined if the reference is `null` or `undefined`. That is if the object property does not exist.
freeCodeCamp
freecodecamp.org › news › javascript-optional-chaining-explained
JavaScript Optional Chaining `?.` Explained - How it Works and When to Use it
August 25, 2020 - let familyTree = { us: { children: {} } } // with _.get const grandChildren = _.get(familyTree, 'us.children.theirChildren', 'got no kids' ); //with optional chaining and null coalescing const nullCoalescing = familyTree?.us?.children?.theirChildren ?? 'got no kids' console.log(nullCoalescing) //got no kids · It also works for objects that may be null or undefined: ... Try it in your browser's console: This is a recent addition and old browsers may need polyfills. You can try it in Chrome or Firefox in the browser's console. If it doesn't work, try turning on JavaScript experimental features by visiting chrome://flags/ and enabling "Experimental JavaScript".
W3Schools
w3schools.com › typescript › typescript_null.php
TypeScript Null & Undefined
Optional chaining is a JavaScript feature that works well with TypeScript's null handling.