TypeScript Type Immutability Checker

is-immutable-type is a TypeScript utility library designed to statically analyze the immutability of TypeScript types within a given program context. It provides detailed classifications for types, distinguishing between `Immutable` (deeply read-only, no modifications possible), `ReadonlyDeep` (deeply immutable data, but methods are not), `ReadonlyShallow` (shallowly immutable, but deep values are not), `Mutable` (shallowly mutable), and `Unknown` (immutability could not be determined). The library is currently on version 5.0.1 and maintains an active release cadence, with several major and minor versions released recently, indicating continuous development. Its key differentiators include precise immutability definitions and a robust override mechanism, allowing developers to specify immutability for types where static analysis alone might be insufficient. It is typically integrated into TypeScript tooling like ESLint plugins for advanced type-aware linting.