formatwhere

FormatWhere is a lightweight, open‑source library designed to simplify conditional data formatting across a variety of programming environments. Initially released in 2018 by a community of developers focusing on data visualization and reporting, the project aims to provide a declarative syntax for applying format rules based on the values and context of data fields. The library supports multiple languages, including JavaScript, Python, and Java, and can be integrated into web applications, server‑side scripts, and desktop software.

The core functionality of FormatWhere revolves around the concept of “format clauses”, which consist of a condition expression and an associated formatting directive. Conditions are expressed using a syntax similar to SQL’s WHERE clause, enabling users to specify criteria such as numeric ranges, string patterns, or date thresholds. When a data element satisfies a clause, the corresponding formatting – for example, color coding, number precision, or text styling – is applied dynamically. Multiple clauses can be chained, and the library resolves conflicts through a priority system defined by the order of declaration.

Key features include an extensible plugin architecture, allowing developers to create custom formatters for specialized output types such as PDF, SVG, or spreadsheet cells. The library also offers built‑in localization support, automatically adapting number and date formats to the target locale. Performance optimizations, such as pre‑compilation of condition trees and memoization of formatting results, enable efficient processing of large datasets with minimal overhead.

Since its inception, FormatWhere has been adopted by several analytics platforms, reporting tools, and educational software projects. The project is maintained on a public repository, with contributions reviewed via a standard pull‑request workflow. Documentation provides comprehensive guides, API references, and example use cases, facilitating rapid adoption for developers seeking to implement conditional formatting without extensive custom code.