fix(stats): prevent 0ms timeDiff breaking movingAverage (#336)

* stats - stat - prevent 0ms timeDiff breaking movingAverage

* chore: remove commitlint

Author: kumavis

.travis.yml

@@ -22,7 +22,6 @@ jobs:
 
     - stage: check
       script:
-        - npx aegir commitlint --travis
         - npx aegir dep-check
         - npm run lint
 

src/stats/stat.js

@@ -182,7 +182,9 @@ class Stats extends EventEmitter {
   _updateFrequencyFor (key, timeDiffMS, latestTime) {
     const count = this._frequencyAccumulators[key] || 0
     this._frequencyAccumulators[key] = 0
-    const hz = (count / timeDiffMS) * 1000
+    // if `timeDiff` is zero, `hz` becomes Infinity, so we fallback to 1ms
+    const safeTimeDiff = timeDiffMS || 1
+    const hz = (count / safeTimeDiff) * 1000
 
     let movingAverages = this._movingAverages[key]
     if (!movingAverages) {