resolves some of the suggested improvements, renames the term period with cycle

test/cycle-length.spec.js

@@ -1,14 +1,14 @@
 import chai from 'chai'
 import { AssertionError } from 'assert'
 
-import periodInfo from '../lib/period-length'
+import cycleInfo from '../lib/cycle-length'
 
 const expect = chai.expect
 
-describe('getPeriodLengthStats', () => {
+describe('getCycleLengthStats', () => {
   it('works for a simple odd-numbered array', () => {
-    const periodLengths = [99, 5, 1, 2, 100]
-    const result = periodInfo(periodLengths)
+    const cycleLengths = [99, 5, 1, 2, 100]
+    const result = cycleInfo(cycleLengths)
     const expectedResult = {
       minimum: 1,
       maximum: 100,
@@ -20,8 +20,8 @@ describe('getPeriodLengthStats', () => {
   })
 
   it('works for a simple even-numbered array', () => {
-    const periodLengths = [4, 1, 15, 2, 20, 5]
-    const result = periodInfo(periodLengths)
+    const cycleLengths = [4, 1, 15, 2, 20, 5]
+    const result = cycleInfo(cycleLengths)
     const expectedResult = {
       minimum: 1,
       maximum: 20,
@@ -32,8 +32,8 @@ describe('getPeriodLengthStats', () => {
     expect(result).to.eql(expectedResult)
   })
   it('works for an one-element array', () => {
-    const periodLengths = [42]
-    const result = periodInfo(periodLengths)
+    const cycleLengths = [42]
+    const result = cycleInfo(cycleLengths)
     const expectedResult = {
       minimum: 42,
       maximum: 42,
@@ -45,20 +45,20 @@ describe('getPeriodLengthStats', () => {
   })
   describe('when args are wrong', () => {
     it('throws when arg object is an empty array', () => {
-      const periodLengths = []
-      expect(() => periodInfo(periodLengths).to.throw(AssertionError))
+      const cycleLengths = []
+      expect(() => cycleInfo(cycleLengths).to.throw(AssertionError))
     })
     it('throws when arg object is not in right format', () => {
       const wrongObject = { hello: 'world' }
-      expect(() => periodInfo(wrongObject).to.throw(AssertionError))
+      expect(() => cycleInfo(wrongObject).to.throw(AssertionError))
     })
     it('throws when arg array contains a string', () => {
       const wrongElement = [4, 1, 15, '2', 20, 5]
-      expect(() => periodInfo(wrongElement).to.throw(AssertionError))
+      expect(() => cycleInfo(wrongElement).to.throw(AssertionError))
     })
     it('throws when arg array contains a NaN', () => {
       const wrongElement = [4, 1, 15, NaN, 20, 5]
-      expect(() => periodInfo(wrongElement).to.throw(AssertionError))
+      expect(() => cycleInfo(wrongElement).to.throw(AssertionError))
     })
   })
 })