Command

Command pattern is a behavioral design pattern that turns a request into a stand-alone object that contains all information about the request. This transformation lets you parameterize methods with different requests, delay or queue a request’s execution, and support undoable operations.

Implementation

interface Command {
  execute(): void;
}
class SimpleCommand implements Command {
  private payload: string;

  constructor(payload: string) {
    this.payload = payload;
  }

  public execute(): void {
    console.log(`SimpleCommand: I can do simple things like printing (${this.payload})`);
  }
}
class ComplexCommand implements Command {
  private receiver: Receiver;
  private a: string;
  private b: string;

  constructor(receiver: Receiver, a: string, b: string) {
    this.receiver = receiver;
    this.a = a;
    this.b = b;
  }

  public execute(): void {
    console.log('ComplexCommand: Complex stuff should be done by a receiver object');
    this.receiver.doSomething(this.a);
    this.receiver.doSomethingElse(this.b);
  }
}

Command

Implementation

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