Harmony Error Fixes

This skill provides solutions for common ArkTS compilation errors and type mismatches encountered during HarmonyOS / OpenHarmony development. Each entry has a focused reference document under references/ and a minimal .ets example under assets/.

When to Use This Skill

Activate this skill whenever any of the following holds:

• The user pastes an ArkTS / .ets compile error from DevEco Studio, hvigor, or ArkCompiler.
• The error contains rule codes from the arkts-no-* family, or mentions any of: ContentType, AppStorage.get, @StorageLink, getLastWindow, AvoidArea, TitleButtonRect, IDataSource, ESObject, LazyForEach, duplicate @Entry, "Possibly 'null'", "Object literal must correspond to some explicitly declared class or interface", "Standalone function ... uses this", "Indexed access is not supported", arkts-no-props-by-index, "Declaration merging is not supported", arkts-no-decl-merging, "Cannot find module", "Maximum call stack", "inferred type cannot be named".
• The user asks how to fix a HarmonyOS build failure or strict ArkTS type error.
• You are reviewing .ets code and want to pre-empt the most common compile errors.

If the task is general ArkTS authoring / migration / style (not a concrete error to fix), prefer arkts-helper instead. Use both together when the user is migrating TS to ArkTS and hits compile errors.

Boundary with Other Skills

This skill covers "how to fix compilation errors", not "how to write code", "how to invoke build commands", or "how to write NDK code". When a fix task involves the following issues, cross-reference the corresponding skill:

Workflow (follow strictly)

1. Identify the error category

Read the user's error message and map it to one row in the Error Categories table below. The mapping is based on the diagnostic text or the API/decorator that triggered it. If the error does not match any row, fall back to arkts-helper/references/04-ts-to-arkts-migration-rules.md for the underlying arkts-no-* rule.

2. Open the matching reference + asset

For each category there are two files:

• references/<topic>.md - root cause, canonical fix, edge-case notes.
• assets/<Topic>.ets - minimal before / after code that compiles cleanly.

Read both for the matched category before editing the user's code. Do not skim only the Quick Reference table.

3. Apply the canonical fix

Apply the fix exactly as documented. Do not silence errors with as any, // @ts-ignore, ESObject, or by deleting type annotations - these patterns are themselves flagged by ArkTS strict mode and will resurface elsewhere.

If the user's code has multiple errors, fix them one category at a time and re-check the build before moving on; one fix often unblocks or reshapes the next error.

4. Cite the reference

When you reply, cite the specific reference file you used, e.g.:

Fix per arkts-debug/references/possibly_null_errors.md.

Error Categories

Quick Reference

Detailed Error Solutions

Notification API Type Errors

• Notification Type Error
• Code Example

Window API Type Errors

• Window Type Inference Error
• Code Example

AppStorage Type Errors

• AppStorage Type Error
• Code Example

Object Spread Type Errors

• Object Spread Type Error
• Code Example

@StorageLink Default Value Errors

• @StorageLink Default Value Error
• Code Example

Object Literal Interface Errors

• Object Literal Interface Error
• Code Example

Object Literal Type Errors

• Object Literal Type Error
• Code Example

Function Return Type Errors

• Function Return Type Error
• Code Example

Arrow Function Conversion Errors

• Arrow Function Conversion Error
• Code Example

Color Property Errors

• Color Property Error
• Code Example

Interface Method Signature Errors

• Interface Method Signature Error
• Code Example

AvoidArea Type Errors

• AvoidArea Type Error
• Code Example

Standalone Function this Errors

• Standalone Function this Error
• Code Example

TitleButtonRect Type Errors

• TitleButtonRect Type Error
• Code Example

Catch Clause Type Errors

• Catch Clause Type Error
• Code Example

ESObject Type Errors

• ESObject Type Error
• Code Example

Resource Conversion Errors

• Resource Conversion Error
• Code Example

Unused Variable Warnings

• Unused Variable Warning
• Code Example

IDataSource Type Errors

• IDataSource Type Error
• Code Example

Duplicate Entry Errors

• Duplicate Entry Error
• Code Example

Possibly Null Errors

• Possibly Null Error
• Code Example

Window Rect/Size Type Errors

• Window Rect/Size Type Error
• Code Example

Indexed Access Errors

• Indexed Access Error
• Code Example

Declaration Merging Errors

• Declaration Merging Error
• Code Example

Inferred Type Naming Errors

• Inferred Type Naming Error
• Code Example

Array Type Inference Errors

• Array Type Inference Error
• Code Example

Module Resolution Errors

• Module Resolution Error
• Code Example

Circular Import Errors

• Circular Import Error
• Code Example