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ts-pattern
Advanced tools
ts-pattern is a pattern matching library for TypeScript that allows for expressive and type-safe pattern matching. It provides a way to handle complex data structures and control flow in a concise and readable manner.
Basic Pattern Matching
This feature allows you to match a value against multiple patterns and execute corresponding actions. The 'otherwise' method provides a default case.
const { match } = require('ts-pattern');
const value = 2;
const result = match(value)
.with(1, () => 'one')
.with(2, () => 'two')
.with(3, () => 'three')
.otherwise(() => 'unknown');
console.log(result); // Output: 'two'
Nested Pattern Matching
This feature allows you to match nested objects and structures, making it easier to handle complex data.
const { match } = require('ts-pattern');
const data = { type: 'user', user: { name: 'Alice', age: 30 } };
const result = match(data)
.with({ type: 'user', user: { name: 'Alice' } }, () => 'Hello Alice')
.with({ type: 'user', user: { age: 30 } }, () => 'User is 30 years old')
.otherwise(() => 'Unknown user');
console.log(result); // Output: 'Hello Alice'
Guard Functions
Guard functions allow you to use custom logic to determine if a pattern matches, providing greater flexibility.
const { match, when } = require('ts-pattern');
const value = 10;
const result = match(value)
.with(when(x => x > 5), () => 'greater than 5')
.with(when(x => x <= 5), () => '5 or less')
.otherwise(() => 'unknown');
console.log(result); // Output: 'greater than 5'
match-ts is another TypeScript pattern matching library. It offers similar functionality to ts-pattern but with a different API design. It focuses on providing a more functional programming style.
typescript-pattern-matching is a library that provides pattern matching capabilities for TypeScript. It is similar to ts-pattern but may have different performance characteristics and API design choices.
fp-ts is a library for functional programming in TypeScript. While it is not solely focused on pattern matching, it provides utilities for handling data structures and control flow in a functional style, which can be used to achieve similar outcomes.
A complete pattern matching library for typescript.
run
, and use otherwise
instead to run the computation ?when
if the predicate is a type guard.FAQs
The exhaustive Pattern Matching library for TypeScript.
The npm package ts-pattern receives a total of 989,302 weekly downloads. As such, ts-pattern popularity was classified as popular.
We found that ts-pattern demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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