coding

Coding Skill

How Appies write code

Purpose

Guidelines and prompts for writing high-quality, maintainable code.

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Core Principles

1. Minimal Invasion

• Change only what's necessary
• Preserve existing patterns
• Don't refactor unless required
• Leave working code alone

2. Readability First

// ❌ Clever
const x = data.reduce((a,b)=>({...a,[b.k]:b.v}),{});

// ✅ Clear
const result = {};
data.forEach(item => {
  result[item.key] = item.value;
});

3. Explicit Over Implicit

// ❌ Magic
const users = await db.get('users');

// ✅ Clear
const users = await database.users.findAll({ 
  where: { active: true },
  limit: 100 
});

4. Error Handling

// Always handle errors
try {
  const result = await riskyOperation();
  return { ok: true, result };
} catch (error) {
  console.error('Operation failed:', error.message);
  return { ok: false, error: error.message };
}

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Code Quality Checklist

Before committing code, check:

• No hardcoded secrets - Use env vars
• Input validation - Check all external inputs
• Error handling - Try/catch with meaningful messages
• No TODOs - Fix or document separately
• Consistent style - Match existing code
• Clear names - Variables/functions describe purpose
• One thing per function - Single responsibility
• Comments explain WHY - Not what (code shows what)

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Appie Coding Prompt

When writing code, follow this structure:

1. Understand Requirements

What problem am I solving?
What are the inputs?
What are the outputs?
What are the edge cases?

2. Check Existing Code

# Find similar implementations
grep -r "similar_function" .
# Read before reimplementing

3. Write Simple First

// Start with the simplest solution
function processData(data) {
  // Basic happy path
  if (!data) return null;
  return data.map(item => item.value);
}

4. Add Error Handling

function processData(data) {
  if (!data) {
    console.error('processData: data is required');
    return { ok: false, error: 'Data required' };
  }
  
  try {
    const result = data.map(item => {
      if (!item.value) throw new Error('Missing value');
      return item.value;
    });
    return { ok: true, result };
  } catch (error) {
    console.error('processData failed:', error.message);
    return { ok: false, error: error.message };
  }
}