Facade Pattern

The Facade Pattern (or façade pattern) is a software design pattern commonly used with object-oriented programming. The name is by analogy to an architectural facade.

A facade is an object that provides a simplified interface to a larger body of code, such as a class library. A facade can:

The Facade design pattern is often used when a system is very complex or difficult to understand because the system has a large number of interdependent classes or its source code is unavailable. This pattern hides the complexities of the larger system and provides a simpler interface to the client. It typically involves a single wrapper class which contains a set of members required by client. These members access the system on behalf of the facade client and hide the implementation details.


A Facade is used when an easier or simpler interface to an underlying object is desired. Alternatively, an adapter can be used when the wrapper must respect a particular interface and must support polymorphic behavior. A decorator makes it possible to add or alter behavior of an interface at run-time.

Pattern Intent
Adapter Converts one interface to another so that it matches what the client is expecting
Decorator Dynamically adds responsibility to the interface by wrapping the original code
Facade Provides a simplified interface

The facade pattern is typically used when:


Example of Facade design pattern in UML

Facade: The facade class abstracts Packages 1, 2, and 3 from the rest of the application. Clients: The objects are using the Facade Pattern to access resources from the Packages.


This is an abstract example of how a client (“you”) interacts with a facade (the “computer”) to a complex system (internal computer parts, like CPU and HardDrive).

/* Complex parts */

class CPU {
  freeze() { /* code here */ }
  jump(position) { /* code here */ }
  execute() { /* code here */ }

class Memory {
  load(position, data) { /* code here */ }

class HardDrive {
  read(lba, size) { /* code here */ }

/* Facade */

class ComputerFacade {
  constructor() {
    this.processor = new CPU();
    this.ram = new Memory();
    this.hd = new HardDrive();

  start() {
    this.ram.load(this.BOOT_ADDRESS,, this.SECTOR_SIZE));

/* Client */

let computer = new ComputerFacade();

Source: Facade pattern. Wikipedia®