MDN Web Docs
developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Operators › Conditional_operator
Conditional (ternary) operator - JavaScript | MDN
The conditional (ternary) operator is the only JavaScript operator that takes three operands: a condition followed by a question mark (?), then an expression to execute if the condition is truthy followed by a colon (:), and finally the expression to execute if the condition is falsy.
freeCodeCamp
freecodecamp.org › news › how-the-question-mark-works-in-javascript
How the Question Mark (?) Operator Works in JavaScript
February 3, 2021 - Instead of the logical OR (||) operator, you can use double question marks (??), or Nullish Coalescing.
Videos
Eran Stiller
eranstiller.com › javascript-double-question-marks
What Is the JavaScript Double Question Marks (??) Operator?
September 24, 2023 - It can be replaced with the nullish ... Double Question Marks operator kicks in to provide a default value when the left-hand side operand, or the first operand, turns out to be null or undefined....
GeeksforGeeks
geeksforgeeks.org › javascript-ternary-operator
JavaScript Ternary Operator | GeeksforGeeks
The ternary operator allows you to quickly decide between two values depending on whether a condition is true or false. ... Condition: A condition that evaluates to true or false. expressionIfTrue: The value or expression is returned if the ...
Published April 15, 2025
vteams
vteams.com › blog › what-is-question-mark-in-javascript
Javascript's Double Question Mark: Meaning and Usage
April 23, 2024 - The ternary operator is basically a shortcut for a traditional if…else statement. Let’s compare JavaScript ternary if, with traditional if…else statement: ... As you can see, the JS question mark operator is only taking one line whereas if…else statement is taking a couple of lines.
MDN Web Docs
developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Operators › Nullish_coalescing
Nullish coalescing operator (??) - JavaScript | MDN
The nullish coalescing operator can be seen as a special case of the logical OR (||) operator. The latter returns the right-hand side operand if the left operand is any falsy value, not only null or undefined. In other words, if you use || to provide some default value to another variable foo, ...
JavaScript.info
javascript.info › tutorial › the javascript language › javascript fundamentals
Conditional branching: if, '?'
To do that, we can use the if statement and the conditional operator ?, that’s also called a “question mark” operator.
Plain English
plainenglish.io › blog › javascript-operator
The JavaScript ?? (Nullish Coalescing) Operator: How Does it Work?
The JavaScript double question mark (??) operator is called the nullish coalescing operator and it provides a default value when a variable or an expression evaluates to null or undefined.
Scaler
scaler.com › home › topics › what is a nullish coalescing operator or double question mark (??) in javascript?
What is JavaScript double question mark (??) - nullish coalescing operator - Scaler Topics
March 28, 2024 - Javascript double question mark can simply be explained as a special case of the logical OR ( || ) operator. When the left-hand side operand is any false value, not just null or undefined, the right-hand side operand is returned in Nullish ...
Built In
builtin.com › software-engineering-perspectives › javascript-question-mark-operator
JavaScript Question Mark (?) Operator Explained | Built In
Summary: The JavaScript question mark operator, or ternary operator, offers a concise alternative to if...else statements. It evaluates a condition and returns one of two values, streamlining variable assignment but potentially reducing code ...
JavaScript in Plain English
javascript.plainenglish.io › javascript-operator-5d3bd92e835e
JavaScript ?? double question mark | JavaScript in Plain English
November 27, 2023 - When you see the JavaScript ?? operator, follow this logic: IF the first value is null/undefined THEN use the default value. If this was useful, you may like · the ternary operator or ·
Codedamn
codedamn.com › news › javascript
Double question mark in JavaScript (Nullish coalescing operator)
January 5, 2023 - In conclusion, the nullish coalescing operator is a new JavaScript feature introduced in the ECMAScript 2020 specification. It is represented by two consecutive question marks (??) and is used to provide a default value for null or undefined values.
SkillReactor Blog
skillreactor.io › home › double question mark javascript operator explained
Double Question Mark JavaScript Operator Explained - SkillReactor Blog
July 8, 2024 - In JavaScript, the double question mark operator represented as ‘??’, is an important tool for handling nullish values and improving code readability. Unlike other operators, such as the logical OR or the ternary operator, the double question mark operator specifically checks for null or ...
Top answer 1 of 2
3
It's called the Short-circuit evaluation and it's a feature of TypeScript. Not JavaScript .
When whatever before ? Is null or undefined, whatever after ?. Won't be called.
That's to avoid errors like: undefined has no property removeEventListener
Edit
I was wrong when I said it's not a feature of JavaScript. It's actually a new feature. Some browsers that are not updated to the latest don't support it yet (like mine)
2 of 2
3
Optional chaining (?.) The optional chaining operator (?.) enables you to read the value of a property located deep within a chain of connected objects without having to check that each reference in the chain is valid.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Optional_chaining
JavaScript.info
javascript.info › tutorial › the javascript language › javascript fundamentals
Nullish coalescing operator '??'
The nullish coalescing operator is written as two question marks ??.
sebhastian
sebhastian.com › javascript-double-question-mark
Learning JavaScript double question mark (??) or the Nullish Coalescing Operator | sebhastian
January 23, 2022 - When you’re inspecting JavaScript ... mark is a logical operator that returns the expression on the right-hand of the mark when the expression on the left-hand is null or undefined...
Aaccsc
aaccsc.com › calcium-bromide › javascript-double-question-mark-operator.html
Javascript double question mark operator
The basic form of a ternary expression is code amp lt expression amp gt amp lt truthy expression amp gt amp lt falsey expressio left pointing double angle quotation mark left pointing guillemet inverted question mark turned question mark asterisk operator Checking for boolean values is easy in JavaScript they are going to be either true or false and typeof a boolean is always quot boolean quot .
freeCodeCamp
freecodecamp.org › news › the-ternary-operator-in-javascript
JavaScript Ternary Operator – Syntax and Example Use Case
January 6, 2023 - Let's see how to do this with the ternary operator: const score = 60 const scoreRating = score > 70 ? "Excellent" : score > 50 ? "Average" : "Do better" console.log(scoreRating) // "Average" Here, you see we have two question marks and two colons. In the first ternary operator, we have the conditional expression score > 70.
CodeForGeek
codeforgeek.com › home › javascript double question mark (??) operator: nullish coalescing explained & examples
JavaScript Double Question Mark (??) Operator: Nullish Coalescing Explained & Examples | CodeForGeek
July 26, 2025 - Solution: Use parentheses to control the order of evaluation in complex expressions. Example: a || b ?? c is not the same as (a || b) ?? c. The JavaScript double question mark operator is called the nullish coalescing operator.
SitePoint
sitepoint.com › blog › javascript › quick tip: how to use the ternary operator in javascript
Quick Tip: How to Use the Ternary Operator in JavaScript — SitePoint
November 6, 2024 - The ternary operator accepts three operands; it’s the only operator in JavaScript to do that. You supply a condition to test, followed by a questions mark, followed by two expressions separated by a colon.