The snippet does it all.

function add(x, y) {
      if (x && y) {
        return x + y;
      } else {
        /**
         * 
         * the error thrown will be instanceof Error class and InvalidArgsError also
         */
        throw new InvalidArgsError();
        // throw new Invalid_Args_Error(); 
      }
    }
    
    // Declare custom error using using Class
    class Invalid_Args_Error extends Error {
      constructor() {
        super("Invalid arguments");
        Error.captureStackTrace(this);
      }
    }
    
    // Declare custom error using Function
    function InvalidArgsError(message) {
      this.message = `Invalid arguments`;
      Error.captureStackTrace(this);
    }
    // does the same magic as extends keyword
    Object.setPrototypeOf(InvalidArgsError.prototype, Error.prototype);
    
    try{
      add(2)
    }catch(e){
      // true
      if(e instanceof Error){
        console.log(e)
      }
      // true
      if(e instanceof InvalidArgsError){
        console.log(e)
      }
    }

The snippet shows it all.

function add(x, y) {
      if (x && y) {
        return x + y;
      } else {
        /**
         * 
         * the error thrown will be instanceof Error class and InvalidArgsError also
         */
        throw new InvalidArgsError();
        // throw new Invalid_Args_Error(); 
      }
    }
    
    // Declare custom error using using Class
    class Invalid_Args_Error extends Error {
      constructor() {
        super("Invalid arguments");
        Error.captureStackTrace(this);
      }
    }
    
    // Declare custom error using Function
    function InvalidArgsError(message) {
      this.message = `Invalid arguments`;
      Error.captureStackTrace(this);
    }
    // does the same magic as extends keyword
    Object.setPrototypeOf(InvalidArgsError.prototype, Error.prototype);
    
    try{
      add(2)
    }catch(e){
      // true
      if(e instanceof Error){
        console.log(e)
      }
      // true
      if(e instanceof InvalidArgsError){
        console.log(e)
      }
    }