Null Coalescing Operator

The null coalescing operator is a binary operator in programming languages that returns the left-hand operand if it is not null; otherwise, it returns the right-hand operand. It provides a concise way to handle null values by specifying a default value when the primary expression evaluates to null. This operator helps simplify code by avoiding verbose null checks and reducing the risk of null reference errors.

Also known as: ?? operator, nullish coalescing operator, coalesce operator, null-coalesce, null coalesce

Why learn Null Coalescing Operator?

Developers should use the null coalescing operator when they need to provide fallback values for potentially null variables, such as in configuration settings, user input handling, or API responses where missing data is common. It is particularly useful in languages like C#, PHP, and JavaScript (as the nullish coalescing operator) to write cleaner, more readable code and improve application robustness by preventing null-related crashes.

Learning Resources

• docs: MDN Web Docs: Nullish coalescing operator (??)
• docs: Microsoft Docs: ?? and ??= operators (C# reference)
• docs: PHP Manual: Null Coalescing Operator
• tutorial: FreeCodeCamp: JavaScript Nullish Coalescing Operator Tutorial
• video: YouTube: Null Coalescing Operator Explained (C#)