callback function (arrow) and class method in TimeOut

I want to trigger 2 functions with a unique timeOut.
The following works fine

    setTimeout(function() {
      function1(); // runs first
      function2(); // runs second
    }, 1000)

But in my case, I have a class method and an callback (arrow function).
It looks like this (minimalized):

    class Timer {
      constructor(callback) {
        this.active = false;
        this.callback = callback;
      }

      cancel() {
        this.active = false;
      }

      set() {
        this.active = true;
        this.timeOut = setTimeout( function() {
          this.cancel();
          this.callback; // HERE is my problem. doesn't run, not casted as a function
        }, 1000)
      }

I get the following error Expected an assignment or function call and instead saw an expression.
Any trick to fix that?