A TypeScript library providing persistent immutable collections and functional programming constructs like Option, Either, and Future.
prelude-ts is a TypeScript library that provides persistent immutable collections (Vector, Set, Map) and functional programming constructs like Option, Either, Predicate, and Future. It solves the problem of managing state predictably in JavaScript and TypeScript by enforcing immutability and offering functional abstractions for common programming tasks.
TypeScript and JavaScript developers looking to adopt functional programming patterns, especially those building applications where immutability, predictable state management, and expressive error handling are important.
Developers choose prelude-ts for its focus on performance (using efficient algorithms), a fluent API that enhances code readability, and strong encouragement of structural equality—making it a practical and accessible entry into functional programming without the overhead of more complex abstractions.
Functional programming, immutable collections and FP constructs for typescript and javascript
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Uses efficient algorithms like HAMT for HashMap/HashSet and bit-mapped vector trie for Vector, avoiding recursion for good runtime performance, with benchmarks available on the wiki.
Prefers chainable methods like list.filter().sortBy() over global functions, enhancing code readability and intuitiveness as shown in the README examples.
Actively encourages defining equals and hashCode for custom types, enabling proper value comparisons in collections and refusing types without these methods to prevent bugs.
Provides Option, Either, Future, etc., without venturing into overly complex abstractions like monad transformers, making functional programming accessible in TypeScript.
Forces developers to implement equals and hashCode for custom types to use collections effectively, adding verbosity and complexity that can deter adoption.
Requires tsconfig adjustments like adding es2015.iterable for ES5 targets, which adds setup complexity and may confuse developers new to TypeScript.
Explicitly excludes higher-level concepts like monad transformers and higher-kinded types, limiting its utility for advanced functional programming use cases.
prelude.ts is an open-source alternative to the following products:
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