Function beginFiberMark

docs/external/js/react-dom.development.js:10398–10415

(fiber, phase)

  };

  var beginFiberMark = function (fiber, phase) {
    var componentName = getComponentName(fiber.type) || 'Unknown';
    var debugID = fiber._debugID;
    var isMounted = fiber.alternate !== null;
    var label = getFiberLabel(componentName, isMounted, phase);

    if (isCommitting && labelsInCurrentCommit.has(label)) {
      // During the commit phase, we don't show duplicate labels because
      // there is a fixed overhead for every measurement, and we don't
      // want to stretch the commit phase beyond necessary.
      return false;
    }

    labelsInCurrentCommit.add(label);
    var markName = getFiberMarkName(label, debugID);
    beginMark(markName);
    return true;
  };

  var clearFiberMark = function (fiber, phase) {
    var componentName = getComponentName(fiber.type) || 'Unknown';