How to access a method from a class from another class?

Your syntax is not legal. There should be an error in your console showing you which line of code is not correct.

If it’s a static method (doesn’t use any instance data), then declare it as a static method and you can directly call it.

If it’s an instance method, then you would typically create an object of type one and then call the method on that object (usually in the constructor).

To make the method static (which appears to be fine in your specific case):

class One {
  static write(){
    console.log("Yes! I did!");
  }
}

class Two {
   tryingMethod(){
     One.write();
   }
}

For the non-static case, you don’t have the proper syntax. It appears you want to create the instance of the One object in a constructor for Two like this:

class One {
  write(){
    console.log("Yes! I did!");
  }
}

class Two {
   constructor() {
       this.one = new One();
   }

   tryingMethod(){
     this.one.write();
   }
}

var x = new Two();
x.tryingMethod();

Note: I’m also following a common Javascript convention of using an identifier that starts with a capital letter for the class/constructor name such as One instead of one.