Parse Error Logs

Parse error and validation output from various tools into structured, actionable data.

When to Use

Quality gate validation (type-check, build, tests)
Parse TypeScript compiler errors
Extract test failure information
Process npm/pnpm command output
Summarize validation results
Feed error data to bug-fixer or other workers

Instructions

Step 1: Receive Raw Output

Accept raw command output as input.

Expected Input:

output: String (raw stdout/stderr from command)
type: String (typescript|jest|npm|build|generic)

Step 2: Identify Error Patterns

Detect error patterns based on type.

TypeScript Patterns:

error TS2322: Type 'string' is not assignable to type 'number'.
src/file.ts(10,5): error TS2322

Jest Patterns:

FAIL src/test.spec.ts
● Test Suite › test name
  Expected: 5
  Received: 3

npm/pnpm Patterns:

ERR! code ENOENT
ERR! syscall open
ERR! path /path/to/file

Build Patterns:

ERROR in ./src/file.ts
Module not found: Error: Can't resolve 'module'

Step 3: Extract Error Details

Parse each error into structured format.

For Each Error Extract:

file: File path (if available)
line: Line number (if available)
column: Column number (if available)
code: Error code (e.g., "TS2322", "ENOENT")
message: Error message
severity: error|warning|info
type: Classification (type-error, test-failure, dependency, etc.)

Step 4: Categorize and Count

Group errors by type and count occurrences.

Categories:

Type errors
Test failures
Dependency issues
Build errors
Linting errors
Runtime errors

Step 5: Return Structured Data

Return complete error analysis.

Expected Output:

{
  "success": false,
  "totalErrors": 15,
  "totalWarnings": 3,
  "summary": {
    "typeErrors": 8,
    "testFailures": 5,
    "buildErrors": 2
  },
  "errors": [
    {
      "file": "src/utils.ts",
      "line": 42,
      "column": 10,
      "code": "TS2322",
      "message": "Type 'string' is not assignable to type 'number'",
      "severity": "error",
      "type": "type-error"
    }
  ],
  "warnings": [
    {
      "file": "src/deprecated.ts",
      "line": 15,
      "code": "TS6133",
      "message": "'oldFunction' is declared but never used",
      "severity": "warning",
      "type": "unused-variable"
    }
  ]
}

Error Handling

Empty Output: Return success with zero errors
Unrecognized Format: Return generic parse with raw message
Partial Parse: Include what was parsed, note unparsable lines
Invalid Type: Warn and default to "generic" parsing

Examples

Example 1: TypeScript Errors

Input:

{
  "output": "src/app.ts(10,5): error TS2322: Type 'string' is not assignable to type 'number'.\nsrc/utils.ts(25,12): error TS2304: Cannot find name 'undefined'.",
  "type": "typescript"
}

Output:

{
  "success": false,
  "totalErrors": 2,
  "totalWarnings": 0,
  "summary": {
    "typeErrors": 2
  },
  "errors": [
    {
      "file": "src/app.ts",
      "line": 10,
      "column": 5,
      "code": "TS2322",
      "message": "Type 'string' is not assignable to type 'number'",
      "severity": "error",
      "type": "type-error"
    },
    {
      "file": "src/utils.ts",
      "line": 25,
      "column": 12,
      "code": "TS2304",
      "message": "Cannot find name 'undefined'",
      "severity": "error",
      "type": "type-error"
    }
  ],
  "warnings": []
}

Example 2: Jest Test Failures

Input:

{
  "output": "FAIL src/utils.test.ts\n  ● Math › addition\n    expect(received).toBe(expected)\n    Expected: 5\n    Received: 3\n      at Object.<anonymous> (src/utils.test.ts:10:15)",
  "type": "jest"
}

Output:

{
  "success": false,
  "totalErrors": 1,
  "totalWarnings": 0,
  "summary": {
    "testFailures": 1
  },
  "errors": [
    {
      "file": "src/utils.test.ts",
      "line": 10,
      "column": 15,
      "code": null,
      "message": "expect(received).toBe(expected) - Expected: 5, Received: 3",
      "severity": "error",
      "type": "test-failure",
      "testName": "Math › addition"
    }
  ],
  "warnings": []
}

Example 3: Successful Build

Input:

{
  "output": "✓ Built successfully\nCompleted in 2.3s",
  "type": "build"
}

Output:

{
  "success": true,
  "totalErrors": 0,
  "totalWarnings": 0,
  "summary": {},
  "errors": [],
  "warnings": []
}

Example 4: Mixed Errors and Warnings

Input:

{
  "output": "Warning: React Hook useEffect has a missing dependency\nerror TS2339: Property 'foo' does not exist on type 'Bar'",
  "type": "typescript"
}

Output:

{
  "success": false,
  "totalErrors": 1,
  "totalWarnings": 1,
  "summary": {
    "typeErrors": 1,
    "lintWarnings": 1
  },
  "errors": [
    {
      "code": "TS2339",
      "message": "Property 'foo' does not exist on type 'Bar'",
      "severity": "error",
      "type": "type-error"
    }
  ],
  "warnings": [
    {
      "message": "React Hook useEffect has a missing dependency",
      "severity": "warning",
      "type": "lint-warning"
    }
  ]
}

Validation

Parses TypeScript errors correctly
Parses Jest test failures
Parses npm/pnpm errors
Parses build errors
Extracts file, line, column when available
Categorizes errors by type
Returns summary counts
Handles successful output (zero errors)
Handles mixed errors and warnings

Supporting Files

patterns.json: Regex patterns for common error formats

parse-error-logs

Parse Error Logs

When to Use

Instructions

Step 1: Receive Raw Output

Step 2: Identify Error Patterns

Step 3: Extract Error Details

Step 4: Categorize and Count

Step 5: Return Structured Data

Error Handling

Examples

Example 1: TypeScript Errors

Example 2: Jest Test Failures

Example 3: Successful Build

Example 4: Mixed Errors and Warnings

Validation

Supporting Files

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