```ts
export function mergeIntervals(intervals: number[][]): number[][] {
  if (!intervals.length) return [];

  // Sort intervals based on start time
  intervals.sort((a, b) => a[0] - b[0]);

  const merged: number[][] = [intervals[0]];

  for (let i = 1; i < intervals.length; i++) {
    const current = intervals[i];
    if (merged[merged.length - 1][1] >= current[0]) {
      // Merge overlapping intervals
      merged[merged.length - 1][1] = Math.max(merged[merged.length - 1][1], current[1]);
    } else {
      // Add non-overlapping interval
      merged.push(current);
    }
  }

  return merged;
}
```