Chore/retire assert

lib/cycle-length.js

@@ -1,5 +1,3 @@
-import assert from 'assert'
-
 export function getCycleLengthStats(cycleLengths) {
   throwIfArgsAreNotInRequiredFormat(cycleLengths)
   const cycleLengthStats = {}
@@ -8,27 +6,27 @@ export function getCycleLengthStats(cycleLengths) {
   })
   cycleLengthStats.minimum = sortedCycleLengths[0]
   cycleLengthStats.maximum = sortedCycleLengths[cycleLengths.length - 1]
-  cycleLengthStats.mean = Math.round(
-    cycleLengths.reduce(getSum) / cycleLengths.length * 100
-  ) / 100
+  cycleLengthStats.mean =
+    Math.round((cycleLengths.reduce(getSum) / cycleLengths.length) * 100) / 100
   // median
   if (cycleLengths.length % 2 == 1) {
-    cycleLengthStats.median = sortedCycleLengths[
-      (cycleLengths.length + 1) / 2 - 1
-    ]
+    cycleLengthStats.median =
+      sortedCycleLengths[(cycleLengths.length + 1) / 2 - 1]
   } else {
     const middle = cycleLengths.length / 2
-    cycleLengthStats.median = (sortedCycleLengths[middle - 1] +
-       sortedCycleLengths[middle]) / 2
+    cycleLengthStats.median =
+      (sortedCycleLengths[middle - 1] + sortedCycleLengths[middle]) / 2
   }
   // corrected standard deviation (based on unbiased sample variance)
   if (cycleLengths.length > 1) {
-    const sumOfSquares = cycleLengths.map(cycleLength => {
-      return Math.pow(cycleLength - cycleLengthStats.mean, 2)
-    }).reduce(getSum)
-    cycleLengthStats.stdDeviation = Math.round(
-      Math.sqrt(sumOfSquares / (cycleLengths.length - 1 )) * 100
-    ) / 100
+    const sumOfSquares = cycleLengths
+      .map((cycleLength) => {
+        return Math.pow(cycleLength - cycleLengthStats.mean, 2)
+      })
+      .reduce(getSum)
+    cycleLengthStats.stdDeviation =
+      Math.round(Math.sqrt(sumOfSquares / (cycleLengths.length - 1)) * 100) /
+      100
   } else {
     cycleLengthStats.stdDeviation = null
   }
@@ -40,10 +38,11 @@ function getSum(total, num) {
 }
 
 function throwIfArgsAreNotInRequiredFormat(cycleLengths) {
-  assert.ok(Array.isArray(cycleLengths), 'Input should be an array.')
-  assert.ok(cycleLengths.length > 0, 'Input array should not be empty.')
-  cycleLengths.forEach(cycleLength => {
-    assert.equal(typeof cycleLength, 'number', 'Elements in the array should be of type number.')
-    assert.ok(!isNaN(cycleLength), 'Elements of array should not be NaN.')
+  if (!Array.isArray(cycleLengths)) throw new Error('Input should be an array.')
+  if (cycleLengths.length < 1)
+    throw new Error('Input array should not be empty.')
+  cycleLengths.forEach((cycleLength) => {
+    if (typeof cycleLength !== 'number' || Number.isNaN(cycleLength))
+      throw new Error('Elements in the array should be of type number.')
   })
-}
+}