ElseValue

ElseValue is a term used in programming and data processing to denote a value chosen as a fallback when no other result is available. It represents the default or fallback outcome that should be used if a condition is not met, a pattern does not match, or an optional value is absent. The concept is especially important for maintaining predictable behavior in expressions, templates, and data transformations where missing or invalid input could otherwise propagate errors.

In conditional expressions, elseValue is the alternative returned if the condition is false. In pattern matching or switch-like constructs, it serves as the branch outcome when no other pattern matches. In languages that model absence with null, undefined, or option types, elseValue is the value supplied when the optional is empty or when an evaluation yields no result.

It is closely related to default values, coalescing operators, and fallback mechanisms. Some languages provide dedicated operators or functions to express elseValue, such as coalesce(a, b) or a ?? b, while in others the logic is implemented with explicit if-else or match constructs. In template engines, elseValue helps keep templates robust by supplying a reasonable value when data is missing.

Common design considerations include choosing an appropriate elseValue that does not obscure data integrity, ensuring consistency across APIs, and avoiding silent masking of real errors. When using elseValue, documenting its precedence and provenance is helpful for maintainability.

See also: default value, null coalescing operator, coalesce, Elvis operator, fallback, option type.