HasArray

HasArray is a term used in programming to denote a predicate or utility that checks whether a value is an array or whether a data structure contains an array. It is not a single standardized API, but rather a concept that appears in various languages and libraries as a means of validating array-typed data.

Forms and usage

HasArray can refer to several related ideas. A simple form is a value check, where hasArray(value) returns true if value is an array. A more specific form tests a property on an object, for example hasArray(obj, prop) returning true if obj[prop] exists and is an array. In validation libraries or schemas, a rule named hasArray may require that a given field be an array, often with optional constraints such as minimum length or item type.

Examples in practice

In JavaScript, a typical check is to use a standard method like Array.isArray(value). Some codebases may expose a hasArray wrapper for readability or consistency with other validation helpers. In other languages, equivalent checks exist, such as isinstance(value, list) in Python. In data schemas, a field might be declared with type: array to enforce that the data conforms to an array structure.

Considerations

Differences between true arrays and array-like objects (such as NodeLists or arguments objects) can affect detection. Performance is usually negligible but can matter in tight validation loops. Cross-language differences mean that the exact implementation of hasArray varies, even though the goal—identifying arrays or array-like structures—remains common.

See also

isArray, Array.isArray, type checking, data validation, array-like objects.