Minimum Number of Refueling Stops LeetCode solution in JavaScript

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var minRefuelStops = function (target, startFuel, stations) {
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  let pq = new MaxPriorityQueue({ compare: (a, b) => b[1] - a[1] });
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  let idx = 0,
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    reachablePosition = startFuel,
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    refuels = 0;
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  // reachablePosition is the farthest position reachable so far
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  while (reachablePosition < target) {
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    // While reachablePosition is >= to the current station's position, add the current station to the heap
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    // These stations are all reachable based on the fuel available
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    // Once reachablePosition is less than a station's position, the while loop ends
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    while (idx < stations.length && reachablePosition >= stations[idx][0]) {
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      pq.enqueue([stations[idx][0], stations[idx][1]]);
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      idx++;
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    }
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    // Next, add fuel from the heap in a greedy manner: the station with the most fuel gets added first
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    // All stations in the heap are reachable, so the position is irrelevant
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    if (pq.size()) {
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      let [pos, fuel] = pq.dequeue();
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      reachablePosition += fuel;
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      refuels++;
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    } else break;
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  }
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  return reachablePosition >= target ? refuels : -1;
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};