Classset

Classset is not a single, formal term; it is a descriptive phrase used in computing to refer to the collection of classes associated with an object or element. Depending on the domain, a class set may denote the set of CSS classes applied to an HTML element, the set of class types available in a program, or the set of target labels in a classification problem.

In web development, the class set of an HTML element comprises its CSS class names. This set determines styling when combined with CSS rules. JavaScript exposes the className property, a space-separated string of class names, and the classList API, which provides tokens and methods such as add, remove, toggle, and contains for manipulating the set.

In programming contexts, a class set can refer to the collection of class types that a component or library uses for reflection, dispatch, or conditional styling. Some UI frameworks expose a computed class set that mixes conditional classes based on state.

In data science and machine learning, the class set denotes the set of possible output labels for a classification task—the target space the model predicts.

Implementation notes: representing a class set with a set data structure helps prevent duplicates. In JavaScript, a Set<string> or a DOMTokenList can model this concept; in Python, a set of strings is common; in databases, a distinct class name table may serve a similar role.

See also: CSS class, classList, DOMTokenList, set, classification.