Allowing measurement of multiple time slots

Changed implementation of measureStart and measureStop, added measurePause function, using an array to store measured time slots

bug fixed when measureStart called multiple times

error in measurePause when label undefined

Author: Yi-Zhou

README.md

@@ -160,9 +160,13 @@ myTimer.getDuration() // 18000
 
 #### `.measureStart(label)`
 
-Start a high-performance measurement with an associated label, you need to use
+Start or continue a high-performance measurement with the associated label, you need to use
 the same label to stop measurement, so make sure you've saved it
 
+#### `.measurePause(label)`
+
+Pause the measurement with the associated label
+
 #### `.measureStop(label)`
 
 Stop the measument with the associated label, returns the number of elapsed ms
@@ -171,12 +175,23 @@ Example:
 
 ```javascript
 
-myTimer.measureStart('label1');
+var label = 'label1';
+
+myTimer.measureStart(label);
 var a = [];
 for (var i = 10000000; i >= 0; i--) {
     a.push(i * Math.random());
 };
-myTimer.measureStop('label1'); // 276 i.e.
+myTimer.measurePause(label);
+
+// do something else
+
+myTimer.measureStart(label);
+for (var i = 0, sum = 0; i < a.length; i++) {
+    sum += a[i];
+};
+var time_elapsed = myTimer.measureStop(label);
+
 ```
 
 > Note!

src/timer.js

@@ -105,12 +105,38 @@
   }
 
   Timer.prototype.measureStart = function (label) {
-    this._.measures[label || ''] = +new Date
+
+    if (!this._.measures[label || '']) this._.measures[label || ''] = []
+
+    this._.measures[label || '']._ = {
+      startTime: +new Date,
+      paused: false
+    }
+    return this
+  }
+
+  Timer.prototype.measurePause = function (label) {
+    var measureArr = this._.measures[label || '']
+    if (measureArr && !measureArr._.paused) {
+      measureArr.push(+new Date - measureArr._.startTime)
+      measureArr._.paused = true
+    }
     return this
   }
 
   Timer.prototype.measureStop = function (label) {
-    return +new Date - this._.measures[label || '']
+    this.measurePause(label)
+    var arr = this._.measures[label || ''],
+      result = 0
+    if (!arr) return result
+
+    var len = arr.length
+    for (var i = 0; i < len; ++i)
+      result += arr[i]
+
+    delete this._.measures[label || '']
+
+    return result
   }
 
   function end () {