Guides Utilities
Detect when code is executed with Bun
Check process.versions.bun to detect whether code is running in Bun. This works in both JavaScript and TypeScript without extra type definitions.
if (process.versions.bun) {
// this code will only run when the file is run with Bun
}Alternatively, check for the Bun global, the same way you'd check for window to detect a browser.
In TypeScript, this is a type error unless @types/bun is installed. Install it with bun add -d @types/bun.
if (typeof Bun !== "undefined") {
// this code will only run when the file is run with Bun
}