CDK TypeScript Rules

Naming Conventions

• Use camelCase for variable and function names.
• Use PascalCase for class names and interface names.
• Use camelCase for interface members.
• Use PascalCase for type names and enum names.

Type System

• Avoid using the any type as it defeats TypeScript’s type checking
• Use specific types or create custom types when needed
• Use union types when a variable can only be one of a limited set of values
• Use destructuring on properties to extract multiple pieces of data from an array or object and assign them to new variables.
• Use the let keyword to declare a local variable instead of using the var keyword
• Always define return types for functions to make the API contract clear
• Use Partial<Type> when all properties of a type should be optional
• Use Required<Type> to make all properties of a type required
• Use Pick to create a type with only the properties you need

Interfaces

• Use interfaces to standardize construct or stack properties ensuring that callers provide the expected parameters.
• Avoid empty interfaces
• Mark interface properties that should not be modified after initialization as readonly

Enums

• Use enums to define sets of related constants
• Export enums at the global level for reuse
• Prefer string enums over numeric enums for better debugging and readability

Linting and Formatting

• Use ESLint to identify issues. Fix them immediately
• Use Prettier as code-formatter