# `@arcjet/runtime`

[Arcjet][arcjet] runtime detection. This package attempts to discover and provide [runtime keys][runtime-keys] as defined by the [WinterCG][wintercg]. - [npm package (`@arcjet/runtime`)](https://www.npmjs.com/package/@arcjet/runtime) - [GitHub source code (`runtime/` in `arcjet/arcjet-js`)](https://github.com/arcjet/arcjet-js/tree/main/runtime) ## What is this? This is an internal utility to help us figure out what platform we are running on. It’s a fork of [`unjs/std-env`][std-env]. We chose to fork so that we can cut away functionality that we do not use and keep our dependency tree as light as possible. We only need the runtime detection. ## When should I use this? You should not use this but use [`unjs/std-env`][std-env] or one of the alternatives instead. This package matches our current needs which are likely different from yours. ## Install This package is ESM only. Install with npm in Node.js: ```sh npm install @arcjet/runtime ``` ## Use ```ts import { runtime } from "@arcjet/runtime"; console.log(runtime()); // => "bun" or "node" and such ``` ## API This package exports the identifier [`runtime`][api-runtime]. There is no default export. This package exports the [TypeScript][] type [`Runtime`][api-runtime-type]. ### `Runtime` This type represents the runtime environments that can be detected. ###### Type ```ts type Runtime = "workerd" | "deno" | "node" | "bun" | "edge-light" | ""; ``` ### `runtime()` Detects which runtime environment your code is currently running in. ###### Returns The detected runtime (`string`), or an empty string if the runtime could not be determined. ## License [Apache License, Version 2.0][apache-license] © [Arcjet Labs, Inc.][arcjet] Derivative work based on [`std-env`][std-env] licensed under [MIT][std-env-license] © Pooya Parsa. Our work cherry picks only what we need. [apache-license]: http://www.apache.org/licenses/LICENSE-2.0 [api-runtime-type]: #runtime [api-runtime]: #runtime-1 [arcjet]: https://arcjet.com [runtime-keys]: https://runtime-keys.proposal.wintercg.org/ [wintercg]: https://wintercg.org/ [std-env-license]: https://github.com/unjs/std-env/blob/7e8cb7b/LICENCE [std-env]: https://github.com/unjs/std-env/blob/d57a5d8/src/runtimes.ts [typescript]: https://www.typescriptlang.org/