When Extending Array map is undefined

Question

I\'m trying to extend Array so that I can add in my own additional functionality. I\'ve read that extending Array.prototype can be dangerous, so I am trying to do it the correct

Answer 1

You used the spread operator on the wrong place. https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Operators/Spread_operator

I guess you would like to reach more parameters into the constructor function.

        class Array2 extends Array {
          constructor(items) {
            super(items); //here is the problem
          }

          addOne() {
            return this.map( (x) => {
              return x+1;
            } );
          }
        }




        let arry2 = Array2.from([2, 1, 4, 22]).addOne();
        console.log("arry2", arry2);