Code Conventions - Code Style Persona

Role

Guide how to write code:

• Maintain consistent code style
• Write readable code
• Create maintainable structure

General Principles

Early Return Pattern

Prefer early returns over nested conditions for better readability.

Size Limits

Target	Limit	When Exceeded
Function/Method	50 lines	Split
File/Class	200 lines	Split into modules
Nesting depth	3 levels	Apply early return

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TypeScript Conventions

Naming

Type	Pattern	Example
Class/Interface/Type	PascalCase	OrderService, UserEntity
Function/Variable	camelCase	calculateTotal, userName
Constant	SCREAMING_SNAKE	MAX_RETRY_COUNT
File	kebab-case or camelCase	order-service.ts
Boolean	is/has/can prefix	isActive, hasPermission

Best Practices

• Use arrow functions when possible
• Prefer const over let, avoid var
• Always declare explicit types
• Use interface for object shapes, type for unions/intersections
• Prefer unknown over any

Avoid

❌ utils.ts, helpers.ts, common.ts, shared.ts

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Python Conventions (PEP-8)

Naming

Type	Pattern	Example
Class	PascalCase	OrderService, UserEntity
Function/Variable	snake_case	calculate_total, user_name
Constant	SCREAMING_SNAKE	MAX_RETRY_COUNT
Module/File	snake_case	order_service.py
Private	leading underscore	_internal_method

Best Practices

• Maximum line length: 79 characters (code), 72 (docstrings)
• Use 4 spaces for indentation (no tabs)
• Two blank lines between top-level definitions
• One blank line between method definitions
• Use type hints (PEP 484)
• Use docstrings for public modules, functions, classes, methods

Import Order (PEP-8)

# 1. Standard library
import os
import sys

# 2. Third-party
import requests
import numpy as np

# 3. Local application
from myapp import utils

Avoid

❌ utils.py, helpers.py, common.py, shared.py

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Java Conventions

Naming

Type	Pattern	Example
Class/Interface	PascalCase	OrderService, UserEntity
Method/Variable	camelCase	calculateTotal, userName
Constant	SCREAMING_SNAKE	MAX_RETRY_COUNT
Package	lowercase	com.example.order
File	Same as class name	OrderService.java

Best Practices

• One public class per file
• Use final for immutable variables
• Prefer composition over inheritance
• Use interfaces for abstraction
• Follow JavaDoc conventions for documentation
• Use Optional instead of null for return values

Avoid

❌ Utils.java, Helpers.java, Common.java, Shared.java

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Checklist

When Writing Code

• Is function/method under 50 lines?
• Is file/class under 200 lines?
• Is nesting under 3 levels?
• Is early return applied?
• Is naming following language conventions?
• Are types/type hints declared?

Before PR

• Consistent code style maintained
• Unnecessary comments removed
• Error handling appropriate
• Linter/formatter passed

Anti-Patterns

• Magic Numbers: Using meaningless numbers directly
• God Function/Class: Giant function/class that does everything
• Callback Hell / Nested Conditionals: Deep nesting
• Copy-Paste Code: Duplicated code
• Generic Naming: utils, helpers, common, shared, misc