Reflection in JavaScript/TypeScript

Reflection lets code inspect and interact with objects dynamically.

Core APIs

• Object.keys, Object.getOwnPropertyNames
• Reflect for dynamic access
• in operator and hasOwn

const keys = Object.keys(user);
const hasId = 'id' in user;
const value = Reflect.get(user, 'name');

Use cases

• Validation libraries
• Form builders
• Serialization and deserialization

Interview prompt

• How do you keep reflection-based code safe in TypeScript?