@devmedic/project-scanner

Fast, parallel, cached detection of what a project actually is — React Native, Expo, TypeScript, JavaScript — from its structure. scanProject(root) returns a ProjectContext describing that structure; nothing here executes rules or reads file contents beyond package.json.

import { scanProject } from '@devmedic/project-scanner';

const context = await scanProject(process.cwd());

context.platform.isReactNative; // boolean
context.platform.isExpo; // boolean
context.platform.isReact; // boolean
context.platform.isNode; // boolean
context.platform.isExpress; // boolean
context.platform.isNestJs; // boolean
context.platform.isNextJs; // boolean
context.language.detected; // 'typescript' | 'javascript' | 'mixed' | 'unknown'
context.packageJson?.workspaces; // readonly string[] | null — the "workspaces" field, if any
context.packageJson?.hasBin; // boolean — whether a "bin" field is present
context.packageJson?.main; // string | null — the "main" field, if any

What it reads

| Signal | Read as | | -------------------------------------------------------- | -------------------------------------------------------------------------------------------- | | package.json | Parsed for name, version, dependencies, devDependencies, workspaces, bin, main | | android/, ios/, src/, assets/ | Existence only (no contents) | | metro.config.{js,cjs,mjs,ts} | First match, in that priority order | | babel.config.{js,cjs,mjs,json}, .babelrc[.js\|.json] | First match, in that priority order | | android/**/build.gradle[.kts], settings.gradle[.kts] | Every match found | | ios/Podfile | Existence | | tsconfig.json + **/*.{ts,tsx,js,jsx} file counts | Language classification |

The **/*.{ts,tsx,js,jsx} count excludes node_modules, dist, build, .expo, android/build, ios/Pods, ios/build, and root-level tooling config (*.config.*, .babelrc*) — a metro.config.js doesn't make a project "JavaScript."

Detection rules

• React Native: a react-native dependency, or a metro.config.* file, or both android/ and ios/ existing together (neither alone is a signal).
• Expo: an expo or expo-modules-core dependency.
• React: isReactNative, or a react dependency.
• Next.js: a next dependency (implies Node.js).
• Express: an express dependency (implies Node.js).
• NestJS: an @nestjs/core dependency (implies Node.js).
• Node.js: any of the above, or an @types/node dependency.
• Language: tsconfig.json present, or .ts/.tsx files with no .js/.jsx → "typescript". .js/.jsx with no TS → "javascript". Both, no tsconfig.json → "mixed". Neither → "unknown".

@devmedic/project-detection-engine builds on these signals — plus workspaces/bin/main for monorepo/CLI/library detection — to decide whether a given file even belongs to the project a rule targets. This package stays framework-detection-only; it has no notion of "rules" or "gating."

Performance

• Parallel: every read for a fresh scan (package.json, directory structure, build files, language file counts) runs concurrently via Promise.all.
• Cached: results are memoized in-process, keyed by resolved root path. A repeat scanProject(root) call costs a single stat on package.json to confirm nothing changed, then returns the cached ProjectContext instantly (fromCache: true).
• Auto-invalidating: if package.json's mtime has changed since it was cached, the cache is bypassed and a fresh scan runs — catches the common case (a dependency added/removed) without a manual cache-clear. It does not catch a purely structural change (e.g. a new android/ folder) that leaves package.json untouched; call clearProjectScannerCache(root) or pass scanProject(root, { cache: false }) for that.

Depends on

• fast-glob