nullsjekk

Nullsjekk, or a null check, is a programming practice used to determine whether a value is null before proceeding with operations that assume it is non-null. The primary purpose is to prevent null reference errors and to define safe handling paths when data is missing.

In practice, null checks are often performed explicitly, such as testing if a variable is null before accessing its fields or methods. Many modern languages provide additional tools to make this safer and more concise, including nullable types, optional values, and special operators that can simplify or replace repetitive checks.

Language features commonly associated with null safety include: Kotlin’s nullable types and the safe call operator; C#’s null-conditional operator and null-coalescing operator; Swift’s optional types; TypeScript’s strictNullChecks and optional chaining; Java’s Optional type; Python’s None checks; and Rust’s Option type. These approaches help developers distinguish between values that may be absent and those that are guaranteed to exist, and they reduce the likelihood of runtime errors from dereferencing null.

Beyond code, null checks are also important in data validation and API design. In databases and data pipelines, nullability constraints and input validation ensure required fields are present or defaulted appropriately. API contracts often specify how null values should be handled and communicated to clients.

Best practices emphasize using language-supported null-safety features when available, avoiding excessive nesting of conditional checks, and considering alternatives such as default values or the null-object pattern to improve readability and maintainability.