true-myth
A library for safe functional programming in JavaScript, with first-class support for TypeScript
option-t
A toolkit of Nullable/Option/Result type implementation in ECMAScript. Their APIs are inspired by Rust's `Option<T>` and `Result<T, E>`.
@expo/results
An efficient, standards-compliant library for representing results of successful or failed operations
happy-rusty
Porting some excellent design implementations from Rust to JavaScript.