Function mergeCoverageRanges

lib/internal/test_runner/coverage.js:717–767

(oldFn, newFn)

}

function mergeCoverageRanges(oldFn, newFn) {
  const mergedRanges = new SafeSet();

  // Keep all of the existing covered ranges.
  for (let i = 0; i < oldFn.ranges.length; ++i) {
    const oldRange = oldFn.ranges[i];

    if (oldRange.count > 0) {
      mergedRanges.add(oldRange);
    }
  }

  // Merge in the new ranges where appropriate.
  for (let i = 0; i < newFn.ranges.length; ++i) {
    const newRange = newFn.ranges[i];
    let exactMatch = false;

    for (let j = 0; j < oldFn.ranges.length; ++j) {
      const oldRange = oldFn.ranges[j];

      if (doesRangeEqualOtherRange(newRange, oldRange)) {
        // These are the same ranges, so keep the existing one.
        oldRange.count += newRange.count;
        mergedRanges.add(oldRange);
        exactMatch = true;
        break;
      }

      // Look at ranges representing missing coverage and add ranges that
      // represent the intersection.
      if (oldRange.count === 0 && newRange.count === 0) {
        if (doesRangeContainOtherRange(oldRange, newRange)) {
          // The new range is completely within the old range. Discard the
          // larger (old) range, and keep the smaller (new) range.
          mergedRanges.add(newRange);
        } else if (doesRangeContainOtherRange(newRange, oldRange)) {
          // The old range is completely within the new range. Discard the
          // larger (new) range, and keep the smaller (old) range.
          mergedRanges.add(oldRange);
        }
      }
    }

    // Add new ranges that do not represent missing coverage.
    if (newRange.count > 0 && !exactMatch) {
      mergedRanges.add(newRange);
    }
  }

  oldFn.ranges = ArrayFrom(mergedRanges);
}

function doesRangeEqualOtherRange(range, otherRange) {
  return range.startOffset === otherRange.startOffset &&