tina
49 lines
1.7 KiB
JavaScript
49 lines
1.7 KiB
JavaScript
import assert from 'assert'
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export default function getCycleLengthStats(cycleLengths) {
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throwIfArgsAreNotInRequiredFormat(cycleLengths)
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const cycleLengthStats = {}
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const sortedCycleLengths = cycleLengths.sort((a, b) => {
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return a - b
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})
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cycleLengthStats.minimum = sortedCycleLengths[0]
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cycleLengthStats.maximum = sortedCycleLengths[cycleLengths.length - 1]
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cycleLengthStats.mean = Math.round(
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cycleLengths.reduce(getSum) / cycleLengths.length * 100
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) / 100
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// median
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if (cycleLengths.length % 2 == 1) {
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cycleLengthStats.median = sortedCycleLengths[
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(cycleLengths.length + 1) / 2 - 1
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]
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} else {
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const middle = cycleLengths.length / 2
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cycleLengthStats.median = (sortedCycleLengths[middle - 1] +
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sortedCycleLengths[middle]) / 2
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}
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// corrected standard deviation (based on unbiased sample variance)
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if (cycleLengths.length > 1) {
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const sumOfSquares = cycleLengths.map(cycleLength => {
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return Math.pow(cycleLength - cycleLengthStats.mean, 2)
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}).reduce(getSum)
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cycleLengthStats.stdDeviation = Math.round(
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Math.sqrt(sumOfSquares / (cycleLengths.length - 1 )) * 100
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) / 100
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} else {
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cycleLengthStats.stdDeviation = null
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}
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return cycleLengthStats
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}
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function getSum(total, num) {
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return total + num
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}
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function throwIfArgsAreNotInRequiredFormat(cycleLengths) {
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assert.ok(Array.isArray(cycleLengths), 'Input should be an array.')
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assert.ok(cycleLengths.length > 0, 'Input array should not be empty.')
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cycleLengths.forEach(cycleLength => {
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assert.equal(typeof cycleLength, 'number', 'Elements in the array should be of type number.')
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assert.ok(!isNaN(cycleLength), 'Elements of array should not be NaN.')
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})
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} |