JavaScript Type Checking Utilities

`is-what` is a lightweight, fully TypeScript-supported utility library providing a comprehensive set of functions for JavaScript type checking, such as `isPlainObject()`, `isArray()`, `isString()`, and many more specific checks. Currently at version `5.5.0`, the library maintains a steady release cadence, frequently adding new type-checking utilities and dependency updates. Its core differentiators include a focus on simplicity, a small footprint, robust TypeScript type inference (automatically narrowing types after checks), and a more intuitive handling of edge cases like `NaN` compared to native JavaScript functions. It explicitly distinguishes between plain objects (`{}`) and class instances, addressing a common pain point in JavaScript development. The library aims to be a straightforward and reliable alternative to more complex or less type-safe existing solutions. Its `v5.x` releases moved to ESM-only and refined its TypeScript integration.