ES6 Classes & Constructors

What creational design pattern is implemented by the Logger class?

class Logger {
  static instance;
  
  constructor() {
    if (Logger.instance) {
      return Logger.instance;
    }
    this.logs = [];
    Logger.instance = this;
  }
  
  log(message) {
    this.logs.push(message);
    console.log(message);
  }
}

Observer pattern
Factory pattern
Singleton pattern
This class implements the Singleton pattern: 1) Ensures only one instance of the class exists, 2) The constructor returns the existing instance if it already exists, 3) Uses a static property to store the instance, 4) Provides a global point of access to the instance, 5) Useful for services that should have only one instance, like logging or configuration, 6) The implementation ensures that all code uses the same Logger instance.
Proxy pattern

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