Flattie Object Flattening Utility

Flattie is a minimalist and highly performant JavaScript utility for recursively flattening nested objects and arrays into a single-depth object. Currently at version 1.1.1, the library maintains a stable release cadence with incremental patches. Its core differentiators include its extremely small bundle size (203B), demonstrated speed via benchmarks against alternatives like `flat` and `flatten-object`, and customizable behavior for key concatenation via a 'glue' string. By default, it automatically omits nullish values (`null`, `undefined`) from the flattened output, a feature that can be toggled. It also ships with TypeScript type definitions, providing a robust developer experience. Its counterpart, `nestie`, provides the reverse operation (expanding flattened objects).