You didn't specify if you were allowed to use ecmascript-6 features or not but presumably you were, since you used let and arrow functions. As an interviewer, I would note that you used those features, yet you iterated over the array using a regular for loop instead of using for...of. That isn't necessarily a bad thing since it demonstrates that you know how to increment a counter in a standard loop and then use that for indexing into the array, but you don't have to if you use a for...of loop.

The technique for sorting the array is good, though because Array.prototype.sort() "sorts the elements of an array in place and returns the array"¹ there isn't really a need to store the value in newArr because resultArr is sorted.

let newArr = resultArr.sort((a,b)=>{

    return a[0]-b[0];
});

You could have just returned the first two elements of resultArr.

Also, const could have been used for any variable that is never re-assigned - including arrays that merely have elements pushed into them - to avoid accidental re-assignment.

¹_{https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort}

You didn't specify if you were allowed to use ecmascript-6 features or not but presumably you were, since you used let and arrow functions. As an interviewer, I would note that you used those features, yet you iterated over the array using a regular for loop instead of using for...of. That isn't necessarily a bad thing since it demonstrates that you know how to increment a counter in a standard loop and then use that for indexing into the array, but you don't have to if you use a for...of loop.

The technique for sorting the array is good, though because Array.prototype.sort() "sorts the elements of an array in place and returns the array"¹ there isn't really a need to store the value in newArr because resultArr is sorted.

let newArr = resultArr.sort((a,b)=>{

    return a[0]-b[0];
});

You could have just returned the first two elements of resultArr.

Also, const could have been used for any variable that is never re-assigned - including arrays that merely have elements pushed into them - to avoid accidental re-assignment.

¹_{https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort}