★★★ Like this project? Leave a star, follow on Twitter or donate to support my work! Thanks. ★★★
## About Sequency Sequency is a lightweight (**5 KB minified**), intensely tested (**200+ tests, 99% coverage**), type-safe functional programming library for processing iterable data such as arrays, sets and maps. It's written in TypeScript, compiles to ES5-compatible JavaScript and works in all current browsers and Node applications. The API is inspired by [Sequences](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.sequences/-sequence/) from the programming language [Kotlin](https://kotlinlang.org/). > Not convinced? [Try Sequency](https://npm.runkit.com/sequency) right in your browser. ## Getting started Download the [latest release](https://github.com/winterbe/sequency/releases) from GitHub or install Sequency from [NPM](https://www.npmjs.com/package/sequency): ```bash npm install --save sequency ``` Alternatively use Sequency from [CDN](https://unpkg.com/sequency/) by adding this to your HTML: ```html ``` ## How Sequency works Sequency is centered around a single class called `Sequence` to process any kind of iterable data such as arrays, sets or maps. The API is inspired by [Kotlin](https://kotlinlang.org/) [Sequences](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.sequences/-sequence/index.html). Sequences can be created by utilizing one of the following functions: ```js import { asSequence, sequenceOf, emptySequence, range, generateSequence, extendSequence } from 'sequency'; ``` - `sequenceOf` accepts one or many values and returns a new sequence. - `asSequence` accepts an iterable (e.g. an array, set or map) and returns a new sequence. - `emptySequence` returns a new empty sequence. - `range` returns as number sequence consisting of all numbers between `startInclusive` and `endExclusive`. - `generateSequence` returns a sequence generated from the given generator function. - `extendSequence` allows extending sequences with user-defined operations (see [example](https://github.com/winterbe/sequency/blob/ac3dbb0f212bb08783d970472c7a76dc921b60ba/test/extendSequence.test.ts)). Each `Sequence` provides a fluent functional API consisting of intermediate and terminal operations. Intermediate functions (e.g. `filter`, `map`, `sorted`) return a new sequence, thus enabling method chaining. Terminal functions (e.g. `toArray`, `groupBy`, `findLast`) return an arbitrary result. Detailed descriptions of all operations are available in the [API docs](https://winterbe.github.io/sequency/). Sequences are **lazily evaluated** to avoid examining all of the input data when it's not necessary. Sequences always perform the minimal amount of operations to gain results. E.g. in a `filter - map - find` sequence both `map` and `find` are executed just one time before returning the single result. ## [API documentation](https://winterbe.github.io/sequency/interfaces/_sequence_.sequence.html) Sequency is fully documented via inline JSDoc comments. [The docs are also available online](https://winterbe.github.io/sequency/interfaces/_sequence_.sequence.html). When using an IDE like Intellij IDEA or Webstorm the docs are available inline right inside your editor. ## Why Sequency? I've built Sequency because I'm using Kotlin for server-side code but for some reasons still use TypeScript and JavaScript for client-side browser code. I find that using the same APIs for collection processing both on client and server is a huge gain in productivity for me. ## License MIT © [Benjamin Winterberg](https://twitter.com/winterbe_)