AI solution for JavaScript Coding Question on BFE.dev
72. implement Observable interval()

Solution:

function interval(duration) {  let count = 0;  return new Observable(observer => {    const intervalId = setInterval(() => {      observer.next(count++);    }, duration);    return () => {      clearInterval(intervalId);    }  });}

We first declare a count variable which will keep track of the sequential numbers emitted by the Observable. Then, we return a new Observable with a function that takes an observer as an argument. We use setInterval() to emit the sequential numbers every duration seconds and pass them to the observer using observer.next(). We also return a clean-up function to clear the interval using clearInterval() when the observer unsubscribes.