Pick Function

Data Manipulation2 functions

Utility Overview

Property Selection Made Simple

Pick functions create new objects by selecting only the properties you need, offering clean data transformation and immutable object manipulation!

🔍 Key Features:

Basic Pick: Select specific properties by key names
Pick By Predicate: Filter properties using custom logic
Type Safety: Full TypeScript support with compile-time checking
Immutability: Original objects remain unchanged
Multiple Implementations:
pick(obj, keys): Direct property selection by key array
pickBy(obj, predicate): Conditional selection using predicate function
Type-safe operations: Maintains property types and relationships
Real-World Applications:
API Responses: Extract only needed fields from large objects
Data Privacy: Remove sensitive fields before sending to client
Form Processing: Select user-input fields from larger state
Database Results: Pick specific columns from query results
Configuration Objects: Extract relevant settings for components

💡 Benefits:

Clean, readable data transformations
Immutable operations prevent side effects
Type safety prevents runtime errors
Memory efficient - only copies needed properties
Functional programming patterns
Easy to test and debug

Details

Property Selection Made Simple

Pick functions create new objects by selecting only the properties you need, offering clean data transformation and immutable object manipulation!

🔍 Key Features:

Basic Pick: Select specific properties by key names
Pick By Predicate: Filter properties using custom logic
Type Safety: Full TypeScript support with compile-time checking
Immutability: Original objects remain unchanged
Multiple Implementations:
pick(obj, keys): Direct property selection by key array
pickBy(obj, predicate): Conditional selection using predicate function
Type-safe operations: Maintains property types and relationships
Real-World Applications:
API Responses: Extract only needed fields from large objects
Data Privacy: Remove sensitive fields before sending to client
Form Processing: Select user-input fields from larger state
Database Results: Pick specific columns from query results
Configuration Objects: Extract relevant settings for components

💡 Benefits:

Clean, readable data transformations
Immutable operations prevent side effects
Type safety prevents runtime errors
Memory efficient - only copies needed properties
Functional programming patterns
Easy to test and debug

Category:Data Manipulation

Functions:pick, pickBy

Concepts:

object manipulationproperty selectionimmutabilitytype safety

Implementation

pick

Time: O(k) | Space: O(k)

export function pick<T extends Record<string, unknown>, K extends keyof T>(
  obj: T,
  keys: K[]
): Pick<T, K> {
  if (obj == null || typeof obj !== 'object') {
    throw new Error('First argument must be an object');
  }
  
  const result = {} as Pick<T, K>;
  
  for (const key of keys) {
    if (Object.prototype.hasOwnProperty.call(obj, key)) {
      // eslint-disable-next-line @typescript-eslint/no-explicit-any
      (result as any)[key] = obj[key];
    }
  }
  
  return result;
}

Usage Examples

Basic property selection

const user = { id: 1, name: 'John', email: 'john@example.com', password: 'secret' };
const publicUser = pick(user, ['id', 'name', 'email']);
// { id: 1, name: 'John', email: 'john@example.com' }