saveValueIfTrue

SaveValueIfTrue is a programming pattern in which a value is saved or updated only when a specified condition evaluates to true. The technique helps control when state changes occur, avoiding unnecessary writes or side effects. It can be implemented as a small function, a conditional statement, or an inline expression.

Common forms include a conditional assignment or a function that receives a condition, a reference or storage target, and the new value. In languages with reference semantics, you can pass the storage target and assign inside the function. In others, you return the updated value. The goal is to produce a new state only if the condition holds, otherwise leave the state unchanged.

Examples

- Pseudocode: if (condition) { storage = newValue; }

- Python: storage = newValue if condition else storage

- JavaScript: if (condition) { storage = newValue; }

Design considerations

SaveValueIfTrue is useful in scenarios like form validation, where a field should be saved only after it is validated, or in configuration loading, where defaults are preserved unless a new value is deemed acceptable. It can improve performance by avoiding unnecessary writes and reduce error propagation by isolating when changes occur. Care is needed to manage references, avoid unintended overrides, and consider thread safety in concurrent contexts. When multiple values depend on a single condition, explicit guards or transactional approaches may be preferable to ensure consistency.

See also

Conditional assignment, guard clause, short-circuit evaluation, state management.