In this article, we will learn how to use and implement the Facade Pattern in TypeScript with an example.

Facade is a structural design pattern that provides a simplified interface to a library, a framework, or any other complex set of classes.

TypeScript Facade Pattern Example

Let's create facade.ts file and add the following code to it:

export class Part1 {
    public method1(): void {
        console.log("`method1` of Part1");
    }
}

export class Part2 {
    public method2(): void {
        console.log("`method2` of Part2");
    }
}

export class Part3 {
    public method3(): void {
        console.log("`method3` of Part3");
    }
}

export class Facade {
    private part1: Part1 = new Part1();
    private part2: Part2 = new Part2();
    private part3: Part3 = new Part3();

    public operation1(): void {
        console.log("`operation1` is called ===");
        this.part1.method1();
        this.part2.method2();
        console.log("==========================");
    }

    public operation2(): void {
        console.log("`operation2` is called ===");
        this.part1.method1();
        this.part3.method3();
        console.log("==========================");
    }
}

Usage

Let's create demo.ts file and add the following code to it:

import { Facade } from "./facade";

export function show() : void {
 var facade: Facade = new Facade();

 facade.operation1();

 facade.operation2();
}

show();

Run:

• Compile the above code using the TypeScript compiler.
• Above code is compiled to plan JavaScript code
• Run Javascript code using node

design_patterns_in_typescript-master\facade> tsc --target ES5 .\demo.ts
design_patterns_in_typescript-master\facade> node .\demo.js
`operation1` is called ===
`method1` of Part1        
`method2` of Part2        
==========================
`operation2` is called ===
`method1` of Part1        
`method3` of Part3        
==========================

When to Use Facade Pattern 

Use the Facade pattern when you need to have a limited but straightforward interface to a complex subsystem.

Use the Facade when you want to structure a subsystem into layers.

All TypeScript Design Patterns

1. Creational Design Patterns

Creational patterns provide various object creation mechanisms, which increase flexibility and reuse of existing code.

1. TypeScript Singleton Pattern Example
2. TypeScript Factory Design Pattern with Example
3. TypeScript Abstract Factory Pattern Example
4. TypeScript Builder Pattern Example
5. TypeScript Prototype Pattern Example

2. Structural Design Patterns

Structural patterns explain how to assemble objects and classes into larger structures while keeping these structures flexible and efficient.

1. TypeScript Bridge Pattern Example
2. TypeScript Adapter Pattern Example
3. TypeScript Decorator Pattern Example
4. TypeScript Composite Pattern Example
5. TypeScript Flyweight Design Pattern Example
6. TypeScript Facade Pattern Example
7. TypeScript Proxy Pattern Example

3. Behavioral Design Patterns

Behavioral design patterns are concerned with algorithms and the assignment of responsibilities between objects.

1. TypeScript Command Pattern Example
2. TypeScript Chain of Responsibility Pattern Example
3. TypeScript Visitor Pattern Example
4. TypeScript Template Method Pattern Example
5. TypeScript Strategy Pattern Example
6. TypeScript State Pattern Example
7. TypeScript Observer Pattern Example
8. TypeScript Memento Pattern Example
9. TypeScript Mediator Pattern Example
10. TypeScript Iterator Pattern Example
11. TypeScript Interpreter Design Pattern Example