Calculate duration

timeDuration.js

"use strict";

const calculateTime = (ranges) => {
  const totalTime = ranges.reduce(
    (acc, x) => {
      const start = x[0];
      const end = x[1];
      let currentTotal = 0;

      // Case E, No overlap
      if (acc.start === 0 || start >= acc.end) {
        acc.start = start;
        acc.end = end;
        currentTotal = end - start;
      } else if (end > acc.end) {
        // Case D, Partial overlap with start in the range
        currentTotal = end - acc.end;
        acc.end = end;
      }

      // Case C, Within the range

      acc.total += currentTotal;
      return acc;
    },
    { total: 0, start: 0, end: 0 }
  );
  return totalTime;
};

const result = calculateTime([
  [Date.now() - 500, Date.now() - 300],
  [Date.now() - 400, Date.now() - 200],
  [Date.now() - 100, Date.now() - 50],
  [Date.now() - 100, Date.now() - 40],
]);

console.log("result expected to be 360, actual:", result.total);

const result1 = calculateTime([
  [100, 200],
  [300, 400],
  [500, 600],
]);
console.log("Test Case 1 expected to be 300, actual:", result1.total);

const result2 = calculateTime([
  [100, 300],
  [150, 250],
  [200, 300],
]);
console.log("Test Case 2 expected to be 200, actual:", result2.total);

const result3 = calculateTime([
  [100, 200],
  [150, 250],
  [300, 400],
  [350, 450],
]);
console.log("Test Case 3 expected to be 300, actual:", result3.total);

const result4 = calculateTime([
  [100, 200],
  [200, 300],
  [300, 400],
]);
console.log("Test Case 4 expected to be 300, actual:", result4.total);

const result5 = calculateTime([[100, 200]]);
console.log("Test Case 5 expected to be 100, actual:", result5.total);

const result6 = calculateTime([
  [100, 200],
  [150, 300],
  [250, 400],
]);
console.log("Test Case 6 expected to be 300, actual:", result6.total);