description: Triage and fix repeated migration errors in batches by root cause. When to use: After build, multiple errors appear that need organized resolution

Purpose: Efficiently handle many errors by grouping and prioritizing fixes.

Input

Complete build output with all errors
Error log or error list
File paths and line numbers

Steps

1. Collect All Errors

Capture complete error list:

Run build and save full output
Count total number of errors
Don't stop at first error - need full picture

Organize errors:

Total Errors: 47

By File:
- src/services/user.service.ts: 8 errors
- src/models/user.model.ts: 3 errors
- src/components/dashboard.component.ts: 12 errors
...

2. Group Errors by Type/Pattern

Categorize by error type:

Import/Module Errors:

Cannot find module 'X'
Module not found
Count: X errors

Type Errors:

Type 'X' is not assignable to type 'Y'
Property 'X' does not exist on type 'Y'
Count: Y errors

Syntax Errors:

Unexpected token
';' expected
Count: Z errors

Configuration Errors:

Build config issues
Missing files
Count: W errors

Example grouping:

## Error Groups

### Group 1: Missing Imports (15 errors)
- Cannot find module '@angular/core' (3 occurrences)
- Cannot find module './user.model' (8 occurrences)
- Cannot find module 'rxjs/operators' (4 occurrences)

### Group 2: Type Mismatches (12 errors)
- Type 'null' not assignable to 'User' (5 occurrences)
- Property 'id' does not exist on type '{}' (7 occurrences)

### Group 3: Undefined Methods (8 errors)
- Property 'size' does not exist on type 'any[]' (8 occurrences)

### Group 4: Missing Properties (6 errors)
- Property 'email' missing in type (6 occurrences)

### Group 5: Configuration (6 errors)
- Cannot find file 'main.ts' (1 occurrence)
- Missing tsconfig option (5 occurrences)

3. Prioritize Error Groups

Priority 1: Blocking Errors (fix first)

Configuration errors that prevent build from starting
Missing files/modules that cause cascade failures
Syntax errors in commonly imported files

Priority 2: High-Frequency Errors (big impact)

Same error repeated many times
Fixing once solves many instances
Errors in base classes/services

Priority 3: Low-Complexity Errors (quick wins)

Simple fixes (e.g., adding missing properties)
Type annotations
Import path corrections

Priority 4: Complex Errors (fix last)

Require architectural changes
Need research
Low frequency but complex

Prioritized plan:

## Fix Order

**Round 1: Configuration (Priority 1)**
1. Fix tsconfig.json
2. Add missing main.ts
Estimated fixes: 6 errors → 41 remaining

**Round 2: Missing Imports Framework (Priority 1+2)**
1. Install @angular/core
2. Install rxjs
Estimated fixes: 7 errors → 34 remaining

**Round 3: Internal Import Paths (Priority 2)**
1. Fix relative paths to models
2. Fix service import paths
Estimated fixes: 8 errors → 26 remaining

**Round 4: Collection Methods (Priority 2+3)**
1. Replace .size() with .length globally
Estimated fixes: 8 errors → 18 remaining

**Round 5: Type Annotations (Priority 3)**
1. Add  | null to nullable types
2. Add missing interface properties
Estimated fixes: 11 errors → 7 remaining

**Round 6: Complex Issues (Priority 4)**
1. Manually review remaining 7 errors

4. Fix Each Group Systematically

For each group in priority order:

Step 4a: Select appropriate skill

Missing import → Skill E1
Type mismatch → Skill E2
Undefined property → Skill E3
Build config → Skill E4
Dependency conflict → Skill E5
Missing feature → Skill E6

Step 4b: Apply fix to all instances

Fix one instance completely
Apply same fix pattern to all similar errors
Use find-and-replace for identical issues

Step 4c: Rebuild after each group

npm run build

Step 4d: Verify errors are resolved

Check error count decreased
Note any new errors that appeared
Confirm expected fixes worked

Step 4e: Update error tracking

✅ Round 1 Complete: 6 errors fixed
   Remaining: 41 errors

✅ Round 2 Complete: 7 errors fixed
   Remaining: 34 errors

5. Handle Cascade Effects

Watch for:

Fixing one error reveals new errors in dependent files
Error count may go up before going down
New error types may appear

If error count increases:

Don't panic - this is normal
New errors are often related to same root cause
Group new errors and prioritize

Example cascade:

Before: 20 import errors (imports commented out)
Fix: Uncomment imports
After: 20 import errors gone, but 15 new type errors appear
Reason: Types are now checked but weren't before

6. Deal with Stubborn Errors

If stuck after 3 attempts:

Document the error:

// TODO: Fix this error - type mismatch
// Error: Type 'X' is not assignable to 'Y'
// Attempted fixes: tried casting, tried changing type
// Need to research proper solution
const value: any = problematicValue;  // Temporary workaround

Add to tracking:

## Known Issues (Deferred)

1. **File:** user.service.ts:45
   **Error:** Complex type inference issue
   **Status:** Deferred - application builds and runs
   **Workaround:** Using 'any' type temporarily
   **Plan:** Research proper typing after core migration complete

Move on:

Don't let one error block entire migration
Fix others first
Come back to difficult ones later
Sometimes fixing other errors makes stubborn ones clear

7. Final Cleanup

When error count is low (< 5):

Review each remaining error individually:

Read error message carefully
Understand root cause
Apply targeted fix
Test fix works

Run final build:

npm run build --verbose

Verify:

✅ 0 errors
✅ Build succeeds
✅ Output files generated
✅ No warnings (or document acceptable warnings)

8. Report Progress

Throughout process, provide updates:

🔨 **Error Fixing Progress**

Initial errors: 47

Round 1 (Config):        47 → 41 (6 fixed)
Round 2 (Framework):     41 → 34 (7 fixed)
Round 3 (Imports):       34 → 26 (8 fixed)
Round 4 (Collections):   26 → 18 (8 fixed)
Round 5 (Types):         18 → 7 (11 fixed)
Round 6 (Manual):        7 → 0 (7 fixed)

✅ **All errors resolved!**
   Total fixed: 47 errors
   Build: SUCCESS

Output

All resolvable errors fixed
Application builds successfully
Documented any deferred issues
Progress tracked and reported

Example Workflow

Initial State

npm run build

ERROR in src/services/user.service.ts:1:31
Cannot find module '@angular/core'

ERROR in src/services/user.service.ts:2:24
Cannot find module 'rxjs/operators'

ERROR in src/services/user.service.ts:15:5
Property 'size' does not exist on type 'any[]'

[... 44 more errors ...]

Total: 47 errors

Group & Prioritize

1. Missing @angular/core (3 files) - Priority 1
2. Missing rxjs (4 files) - Priority 1
3. Collection .size() → .length (8 instances) - Priority 2
4. Type mismatches (32 instances) - Priority 3

Fix Round 1

npm install @angular/core @angular/common
npm install rxjs

npm run build
# Now: 40 errors (7 fixed)

Fix Round 2

// Find all: .size()
// Replace: .length
# Now: 32 errors (8 fixed)

Fix Round 3

// Fix type annotations one by one
# Now: 0 errors (32 fixed)

Success

✅ Build successful!
   Fixed: 47 errors
   Time: 45 minutes

name	e7-systematic-batch-fix
description	Triage and fix repeated migration errors in batches by root cause.

Skill E7: Systematic Error Batch Fix