elementswhere

Elementswhere is a hypothetical declarative querying interface designed to filter collections of elements, such as DOM nodes or data objects, by applying predicates similar to a SQL WHERE clause. It emphasizes readable, composable filters that can be expressed in a concise syntax and applied consistently across different data sources.

In its typical design, elementswhere provides a filter operator, often named where, which accepts a predicate expression and returns a subset of the original collection. Predicates can reference element properties, derive values through functions, and combine conditions with logical operators. The goal is to enable expressive filtering without requiring imperative loops.

Syntax and examples are language-agnostic in concept. A JavaScript-like usage might take the form: elements.where({type: "button", enabled: true}) or elements.where("price < 100 && inStock"). Many implementations support both object-based predicates for simple matches and string-based expressions for more complex logic, along with chaining for multi-step filtering.

Implementation considerations include compatibility with arrays of objects or with DOM element collections, and the ability to integrate with existing utility libraries. Performance depends on predicate complexity, data size, and evaluation strategy, with optimizations such as short-circuiting and indexing being common enhancements.

Use cases for elementswhere include client-side UI filtering, data processing pipelines, and server-side query construction where a consistent, declarative approach to element selection is desirable. It sits alongside traditional filtering methods and predicate-based queries, offering an explicit, element-centric perspective.

See also: filter, query language, predicate, DOM, functional programming.