{"id":10736,"library":"detect-ts-node","title":"Detect if Running in TS Node","description":"The `detect-ts-node` package is a utility designed to programmatically determine if the currently executing JavaScript or TypeScript code is running within a `ts-node` environment. It provides a single boolean export that is `true` when `ts-node` is active and `false` otherwise. The current stable version is 1.0.5. Given its highly focused and stable nature, the package likely maintains a very low release cadence, with updates primarily addressing internal `ts-node` changes or minor bug fixes. A key differentiator is its simplicity and direct implementation, based on established discussions within the `ts-node` community, making it a reliable choice for developers who need to implement conditional logic, configuration adjustments, or specific debugging behaviors when operating under `ts-node` versus a pre-compiled JavaScript environment. It explicitly targets `ts-node` detection, distinguishing it from broader TypeScript compilation environment checks.","status":"active","version":"1.0.5","language":"javascript","source_language":"en","source_url":"https://github.com/yorickdevries/detect-ts-node","tags":["javascript","detect","ts-node","typescript"],"install":[{"cmd":"npm install detect-ts-node","lang":"bash","label":"npm"},{"cmd":"yarn add detect-ts-node","lang":"bash","label":"yarn"},{"cmd":"pnpm add detect-ts-node","lang":"bash","label":"pnpm"}],"dependencies":[],"imports":[{"note":"The package exports a single boolean value as its default export. Attempting to use named import syntax for `detectTSNode` will result in a runtime error or a build error.","wrong":"import { detectTSNode } from 'detect-ts-node';","symbol":"detectTSNode","correct":"import detectTSNode from 'detect-ts-node';"},{"note":"In CommonJS environments, `require('detect-ts-node')` directly resolves to the default export. Explicitly accessing `.default` is unnecessary and can be incorrect if the environment does not correctly interop ESM default exports.","wrong":"const detectTSNode = require('detect-ts-node').default;","symbol":"detectTSNode","correct":"const detectTSNode = require('detect-ts-node');"},{"note":"While the package ships TypeScript types, `detectTSNode` itself is a simple boolean (`boolean` type). No dedicated type import is required or available for this value.","symbol":"type of detectTSNode","correct":"// No specific type import is needed, as `detectTSNode` is a boolean value.\n// TypeScript's type inference handles it automatically."}],"quickstart":{"code":"import detectTSNode from \"detect-ts-node\";\n\nfunction initializeApplication() {\n  if (detectTSNode) {\n    console.log(\"TS Node detected. Applying development-specific configurations.\");\n    // Example: Dynamically load '.env.development' or enable hot-reloading\n    process.env.NODE_ENV = 'development';\n    // Potentially load a different config module\n    // const config = require('./config.ts-node').default;\n  } else {\n    console.log(\"Not running in TS Node. Standard production or compiled JS environment.\");\n    // Example: Load '.env.production' or rely on pre-compiled assets\n    process.env.NODE_ENV = 'production';\n    // const config = require('./config.js').default;\n  }\n  console.log(`Application environment set to: ${process.env.NODE_ENV}`);\n}\n\ninitializeApplication();","lang":"typescript","description":"Demonstrates how to import and use the `detectTSNode` boolean value to conditionally execute logic or set configurations based on whether the code is running within a `ts-node` environment."},"warnings":[{"fix":"Always test `detect-ts-node` against new major `ts-node` versions if its accuracy is critical to your application's conditional logic. Monitor the `detect-ts-node` GitHub repository for updates addressing `ts-node` changes.","message":"The detection mechanism relies on internal heuristics that `ts-node` exposes. While generally robust, future major versions of `ts-node` could theoretically change these internals, potentially leading to incorrect detection in `detect-ts-node` without a corresponding package update.","severity":"gotcha","affected_versions":">=1.0.0"},{"fix":"If you need to detect broader TypeScript compilation contexts, implement custom checks based on specific environment variables (e.g., `TS_JEST` for Jest) or specific build tool flags that indicate their presence.","message":"This package is specifically designed to detect `ts-node`. It does not detect other TypeScript compilation environments such as `ts-jest`, `ts-loader` for Webpack, `esbuild` with TypeScript, or direct `tsc` compilation. Its scope is limited to `ts-node`.","severity":"gotcha","affected_versions":">=1.0.0"}],"env_vars":null,"last_verified":"2026-04-19T00:00:00.000Z","next_check":"2026-07-18T00:00:00.000Z","problems":[{"fix":"Ensure you are treating `detectTSNode` as a boolean (`if (detectTSNode) { ... }`) and not invoking it. For CommonJS, use `const detectTSNode = require('detect-ts-node');` directly without `.default` if you encounter this.","cause":"Attempting to call `detectTSNode` as a function when it is a boolean value, or incorrect CommonJS interop with ESM default exports.","error":"TypeError: (0, _detectTsNode.default) is not a function"},{"fix":"Change `import { detectTSNode } from 'detect-ts-node';` to `import detectTSNode from 'detect-ts-node';` to correctly import the default export.","cause":"Attempting to import the default export using named import syntax in an ESM module.","error":"SyntaxError: Named export 'detectTSNode' not found. Did you mean 'default'?"}],"ecosystem":"npm"}