A simple Javascript stopwatch. The stopwatch records metadata about the stopwatch execution, such as when the stopwatch was started, stopped, and resumed. All stopwatch measurements are taken using UTC time, to account for timezone changes. The stopwatch also records when each split was taken and if/when the split was modified.

var stopwatchInstance  = new BasicStopWatch();

stopwatchInstance.start();

to get the total duration:

var currentTotalDuration = stopwatchInstance.totalDuration();

To stop the stopwatch:

var totalDuration = stopwatchInstance.stop()

To resume a stopped stopwatch:

stopwatchInstance.resume();

To reset a stopwatch, use the reset method:

stopwatchInstance.reset();

But, let's say that you (or an end-user) hit the start button too early/late. Use the setStartValue with the correct unix-timestamp of when the stopwatch should have started to correct the stopwatch.

var correctStart = new Date(2020, 13, 18),
    correctStartTimestamp = correctStart.getTime();
stopwatchInstance.setStartValue(correctStartTimestamp);

NOTE: setStartValue will modify the first split and lap to account for the difference between the old startValue and the new one. The modification will be reflected in the metadata.lastModified date.

This can also be done for the stop using setStopValue function:

var correctStop = new Date(2020, 13, 22),
    correctStopTimestamp = correctStart.getTime();
stopwatchInstance.setStopValue(correctStopTimestamp);

NOTE: setStopValue will modify the last split and lap to account for the difference between the old stopValue and the new one. The modification will be reflected in the metadata.lastModified date.

To use a stopwatch that support splits, using the SplitStopwatch:

var stopwatchInstance = new SplitStopwatch();

To take a split for the current time use the addSplit method:

var splitValue = stopwatchInstance.addSplit();

To find the duration of the stopwatch since the last split, use the splitDuration method. The value will be returned in milliseconds:

currentSplitDuration = stopwatchInstance.splitDuration();

To read all the existing splits taken on the stopwatch:

for (var i = 0; i < stopwatchInstance.splits.length; i++) {
    var splitValue = stopwatchInstance.splits[i];
    console.log(splitValue);
}

Use the update method to change a split at a given index to a given value. This method will recalculate the next split to account for the change to the previous split:

var index = 1;
    value = 257000; // 4 minutes, 17 seconds
stopwatchInstance.update(index, value);

which will set the second split to 257000 milliseconds

To add a new split to the stopwatch, use the addRelativeSplit(value), where the value is the number of milliseconds since the start of the stopwatch:

var value = 240000;
stopwatchInstance.addRelativeSplit(value);

If there is a split after the one specified, its duration will be modified to account for the newly-added split.

To delete a split, use the removeSplit method, where the index specifies the index of the split to remove. This method will also modify the next split to account for the change.

var index = 2;
stopwatchInstance.removeSplit(index);

To record laps, use the LapStopwatch:

var lapDistance = 400,
    lapUnits = 'Meters',
    stopwatchInstance = new LapStopwatch(lapDistance, lapUnits);

To record a lap, use the addLap method:

var lap = stopwatchInstance.addLap();

to get the current lap duration, use the lapDuration method:

var currentLapDuration = stopwatchInstance.lapDuration();

To get metadata about a stopwatch, using the metadata property:

var metadata = stopwatch.metadata;

To get the start time of a stopwatch, use the startValue property:

var startTimestamp = stopwatch.startValue;

To find out if the stopwatch is currently being used to time something, use the isRunning method:

if (stopwatchInstance.isRunning()) {
    stopwatchInstance.stop();
}

To find out if the stopwatch has been used and not been reset, use the isActive method:

if (!stopwatchInstance.isActive()) {
    stopwatchInstance.start();
}

To iterate over existing splits in the stopwatch:

for (var i = 0; i < splitStopwatch.splits.length; i++) {
  var split = splitStopwatch.splits[i];
}

To iterate over existing laps in the stopwatch:

for (var i = 0; i < lapStopwatch.laps.length; i++) {
  var lap = lapStopwatch.laps[i];
}