Bug in Data Structures: Create a Priority Queue Class

Challenge have a condition: The priority queue should return items with a higher priority before items with a lower priority and return items in first-in-first-out order otherwise.

this.dequeue = () => { let el = this.collection.pop(); return el[0]}

But solution approves when I return items with lower priority first, not higher.

this.dequeue = () => { let el = this.collection.shift(); return el[0]}