# tsoption > Correct, easy to use Option type for TypeScript Latest version **0.7.0** (published 2018-10-03) · MIT license · 0 weekly downloads ## Install ```sh npm install tsoption pnpm add tsoption yarn add tsoption bun add tsoption ``` ## Health **Score 25/100 (F)** — status: abandoned. Positive: has types; no vulnerabilities; high quality score. Warnings: low downloads; no esm support; pre 1.0. Negative: abandoned; low maintenance score. ## Facts | | | |---|---| | Version | 0.7.0 | | Published | 2018-10-03 | | First published | 2017-07-08 | | Weekly downloads | 0 | | License | MIT | | TypeScript types | bundled | | Module format | CommonJS | | Dependencies | 0 | | Unpacked size | 131.3 KB | | Known vulnerabilities | 0 | | Install scripts | no | | GitHub stars | 60 | | Author | Boris Cherny | | Maintainers | bcherny | | Keywords | adt, algebra, algebraic data type, haskell, option, optional, maybe, monad, fantasy, fantasyland, functor, sanctuary, scala, typescript, type, typesafe, null, safe | ## Links - npm: https://www.npmjs.com/package/tsoption - Repository: https://github.com/bcherny/tsoption - npm.io page: https://npm.io/package/tsoption ## Alternatives - [@openai/codex-sdk](https://npm.io/package/@openai/codex-sdk.md) — 731.4K weekly downloads - [babel-plugin-transform-react-jsx](https://npm.io/package/babel-plugin-transform-react-jsx.md) — 565.0K weekly downloads - [babel-helper-remove-or-void](https://npm.io/package/babel-helper-remove-or-void.md) — 508.5K weekly downloads - [@pnpm/store-controller-types](https://npm.io/package/@pnpm/store-controller-types.md) — 186.9K weekly downloads - [react-native-signature-canvas](https://npm.io/package/react-native-signature-canvas.md) — 155.6K weekly downloads ## Recent versions - 0.7.0 (latest) — 2018-10-03 - 0.6.0 — 2018-05-06 - 0.5.0 — 2018-04-29 - 0.4.1 — 2018-02-26 - 0.4.0 — 2018-01-28 - 0.3.6 — 2017-07-26 - 0.3.5 — 2017-07-26 - 0.3.3 — 2017-07-26 - 0.3.2 — 2017-07-26 - 0.3.1 — 2017-07-26 - 0.3.0 — 2017-07-26 - 0.2.0 — 2017-07-08 - 0.1.0 — 2017-07-08 ## README # tsoption [![Build Status][build]](https://circleci.com/gh/bcherny/tsoption) [![npm]](https://www.npmjs.com/package/tsoption) [![mit]](https://opensource.org/licenses/MIT) [![fantasy]](https://github.com/fantasyland/fantasy-land#monad) [build]: https://img.shields.io/circleci/project/bcherny/tsoption.svg?branch=master&style=flat-square [npm]: https://img.shields.io/npm/v/tsoption.svg?style=flat-square [mit]: https://img.shields.io/npm/l/tsoption.svg?style=flat-square [fantasy]: https://img.shields.io/badge/fantasyland-Monad-ff4ba4.svg?style=flat-square > Correct, easy to use Option type for TypeScript. Like Scala options; see the [introductory blog post](https://performancejs.com/post/ewff3hj/Options-in-TypeScript). ## Installation ```sh # Using Yarn: yarn add tsoption # Or, using NPM: npm install tsoption --save ``` ## Usage *Note: You can use JavaScript instead of TypeScript, but it's not as fun.* ```ts let a = Option.of(3) // Some(3) .flatMap(_ => Some.of(5)) // Some(5) .map(_ => 'a') // Some('a') .orElse(Option.of('b')) // Some('a') (non-string type gives a compile error) .getOrElse('c') // 'a' let b = Option.of('a') // Some('a') .flatMap(_ => new None) // None() (flatMap can map to any type) .orElse(Option.of('b')) // Some('b') (non-string type gives a compile error) .get() // 'b' ``` ## API *Note: The types of each of the expressions below are known at compile time.* ```ts // Create an option Option.of(3) // Some(3) Option.of('abc') // Some('abc') Option.of(null) // None (for convenience) Option.of(undefined) // None (for convenience) Some.of(3) // Some(3) Some.of(null) // Some(null) new Some([1, 2, 3]) // Some([1, 2, 3]) new None // None // #flatMap Some.of(3).flatMap(_ => Some.of(_ * 2)) // Some(6) None.of().flatMap(() => Some.of(2)) // None // #get Some.of(3).get() // 3 None.of().get() // COMPILE ERROR! Can't call get() on None // #getOrElse Some.of(1).getOrElse(2) // 1 None.of().getOrElse(2) // 2 // #isEmpty Some.of(2).isEmpty() // false (known at compile time too!) None.of().isEmpty() // true (known at compile time too!) // #map Some.of(2).map(_ => _ * 2) // Some(4) None.of().map(() => 2) // None (known at compile time too!) // #nonEmpty Some.of(2).nonEmpty() // true (known at compile time too!) None.of().nonEmpty() // false (known at compile time too!) // #orElse Some.of(2).orElse(Option.of(3)) // Some(2) None.of().orElse(Option.of(3)) // Some(3) // #toString Some.of(2).toString() // "Some(2)" None.of().toString() // "None" ``` ## Fantasyland TSOption is [Fantasyland](https://github.com/fantasyland/fantasy-land)-compliant. It implements: - [x] [Applicative](https://github.com/fantasyland/fantasy-land#applicative) - [x] [Apply](https://github.com/fantasyland/fantasy-land#apply) - [x] [Chain](https://github.com/fantasyland/fantasy-land#chain) - [x] [Functor](https://github.com/fantasyland/fantasy-land#functor) - [x] [Monad](https://github.com/fantasyland/fantasy-land#monad) ### Fantasyland-Compatible API ```ts import * as fl from 'fantasy-land' const {ap, chain, map, of} = fl // Create an option Option[of](3) // Some(3) Option[of]('abc') // Some('abc') Option[of](null) // None Option[of](undefined) // None // #chain Option[of](3)[chain](_ => Option[of](_ * 2)) // Some(6) Option[of](null)[chain](() => Option[of](2)) // None (known at compile time too!) // #map Option[of](2)[map](_ => _ * 2) // Some(4) Option[of](null)[map](() => 2) // None (known at compile time too!) // #ap Option[of](2)[ap](Option[of]((_: number) => _ * 2)) // Some(4) Option[of](null)[ap](Option[of](() => 2)) // None (known at compile time too!) ``` ## Tests ```sh npm test ``` ## License MIT --- _Source: https://npm.io/package/tsoption · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._