The chans package is a Go library that provides a set of generic channel operations for building concurrent pipelines. It offers functions for filtering, mapping, reducing, batching, windowing, de-duplication, and routing data through channels. Each function is designed to be composable, allowing developers to construct complex data processing flows by combining these building blocks. The package stands out for its consistent handling of context cancellation across all functions, ensuring that pipelines can be gracefully terminated. A key insight in the implementation is the use of internal helper functions (forEach, whileTrue, untilErr) that abstract the common pattern of iterating over a channel with context awareness. This reduces boilerplate and ensures that every function correctly handles cancellation and channel closure. The Merge function, which fans in multiple input channels using goroutines, is another example of careful concurrency management. Designed to be unopinionated and flexible, chans gives developers full control over channel lifecycle and concurrency patterns. Unlike some other concurrency libraries, it does not impose specific goroutine patterns or error handling strategies, instead providing low-level primitives that can be adapted to various use cases. The package has zero external dependencies beyond the Go standard library, making it easy to integrate into any Go project.