alex-popov-tech/typescript-detector

Purpose

Detect TypeScript presence and available compilation commands in a repository, returning structured JSON data specifically formatted for the quality-gates-compilation agent to consume.

When to Use

Invoke this skill during Phase 0 (Environment Detection) of the quality-gates-compilation agent workflow to:

• Verify TypeScript is configured in the repository
• Identify available TypeScript compilation command
• Locate command source for the agent to read directly

This skill should NOT be invoked for general code review or type checking tasks - only for environment detection.

Detection Process

Step 1: Check for TypeScript Configuration

Search for TypeScript configuration file using Glob tool:

• tsconfig.json

If NO configuration file found:

• Set typescriptDetected: false
• Return early with minimal JSON structure

If configuration file found:

• Set typescriptDetected: true
• Record config file path
• Proceed to Step 2

Step 2: Detect TypeScript Compilation Command

Search for TypeScript compilation commands in priority order:

2a. Check CLAUDE.md (Highest Priority)

If CLAUDE.md exists:

• Read the file
• Search for sections: "Type checking", "TypeScript", "Development Commands", "Common Commands", "Compilation"
• Look for command patterns:
  • tsc, typecheck, type-check, compile, make compile, npm run compile
• Extract exact command mentioned
• Record CLAUDE.md as source if command found

2b. Check package.json Scripts

Read package.json and examine the scripts section:

Compilation commands (look for these script names):

• "compile"
• "type-check"
• "typecheck"
• "tsc"
• "build:types"
• Extract as: npm run <script-name>

Record package.json as source if command found.

2c. Check Makefile

If Makefile exists:

• Read the file
• Search for targets containing tsc or compile
• Common target patterns:
  • compile, typecheck, type-check, tsc
• Extract as: make <target-name>
• Record Makefile as source if command found

2d. Fallback Command

If no command found in any source:

• Use fallback command: npx tsc --noEmit
• Record source as: "fallback"

Step 3: Build JSON Response

Construct JSON object with this exact structure:

{
  "typescriptDetected": true,
  "configFile": {
    "path": "tsconfig.json",
    "exists": true
  },
  "command": {
    "compile": "npm run compile",
    "source": "package.json"
  }
}

Field Specifications:

• typescriptDetected (boolean): true if tsconfig.json found, false otherwise
• configFile (object): TypeScript configuration file details
  • path (string): Relative path to tsconfig.json (always "tsconfig.json")
  • exists (boolean): Whether file exists (always true if detected)
• command (object): Compilation command details
  • compile (string): Exact command to run for type checking
  • source (string): Where command was found ("CLAUDE.md", "package.json", "Makefile", or "fallback")

Step 4: Return JSON

Output the JSON structure in a code block with clear formatting:

## TypeScript Detection Results

```json
{
  "typescriptDetected": true,
  "configFile": {
    "path": "tsconfig.json",
    "exists": true
  },
  "command": {
    "compile": "npm run compile",
    "source": "package.json"
  }
}
```

**Summary:**
- TypeScript detected: Yes/No
- Config file: tsconfig.json
- Command source: <source>

Priority Rules

1. Command Priority: CLAUDE.md > package.json > Makefile > fallback
2. Use First Match: Use the first match found from priority list
3. Source Transparency: Always record where command was found
4. Single Command: TypeScript only needs one compile command (unlike ESLint which has check + fix)

Edge Cases

tsconfig.json found but no command:

{
  "typescriptDetected": true,
  "configFile": {
    "path": "tsconfig.json",
    "exists": true
  },
  "command": {
    "compile": "npx tsc --noEmit",
    "source": "fallback"
  }
}

No tsconfig.json found:

{
  "typescriptDetected": false,
  "configFile": {
    "path": "tsconfig.json",
    "exists": false
  },
  "command": {}
}

Command found in multiple sources:

• Use highest priority source (CLAUDE.md wins)
• Record only the used source

Multiple tsconfig files:

• Only check for root tsconfig.json
• Project-specific configs (tsconfig.build.json, etc.) are not relevant for type checking

Integration with quality-gates-compilation

The quality-gates-compilation agent will:

1. Invoke this skill during Phase 0
2. Parse the returned JSON structure
3. Use typescriptDetected to decide whether to proceed or exit
4. Use command.compile for running type checks
5. Read file listed in command.source if needed for additional context

The JSON structure is designed to provide everything the compilation agent needs without requiring additional file reads for command detection.