Client - init distance converter

fittrackee_client/src/types/units.ts

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+export type TUnitSystem = 'imperial' | 'metric'
+
+export type TUnit = 'ft' | 'mi' | 'm' | 'km'
+
+export type TFactor = {
+  [k in string]: Record<string, number>
+}
+
+export interface IUnit {
+  unit: TUnit
+  system: TUnitSystem
+  multiplier: number
+}

fittrackee_client/src/utils/units.ts

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+import { IUnit, TFactor, TUnit } from '@/types/units'
+
+export const units: Record<string, IUnit> = {
+  ft: {
+    unit: 'ft',
+    system: 'imperial',
+    multiplier: 1,
+  },
+  mi: {
+    unit: 'mi',
+    system: 'imperial',
+    multiplier: 5280,
+  },
+  m: {
+    unit: 'm',
+    system: 'metric',
+    multiplier: 1,
+  },
+  km: {
+    unit: 'm',
+    system: 'metric',
+    multiplier: 1000,
+  },
+}
+
+const factors: TFactor = {
+  metric: {
+    imperial: 3.280839895,
+    metric: 1,
+  },
+  imperial: {
+    metric: 1 / 3.280839895,
+    imperial: 1,
+  },
+}
+
+export const convertDistance = (
+  distance: number,
+  from: TUnit,
+  to: TUnit,
+  digits: number | null = 3
+): number => {
+  const unitFrom = units[from]
+  const unitTo = units[to]
+  const convertedDistance =
+    (distance * unitFrom.multiplier * factors[unitFrom.system][unitTo.system]) /
+    unitTo.multiplier
+  if (digits !== null) {
+    return parseFloat(convertedDistance.toFixed(digits))
+  }
+  return convertedDistance
+}

fittrackee_client/tests/unit/utils/units.spec.ts

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+import { assert } from 'chai'
+
+import { TUnit } from '@/types/units'
+import { convertDistance } from '@/utils/units'
+
+describe('convertDistance', () => {
+  const testsParams: [number, TUnit, TUnit, number][] = [
+    [0, 'm', 'ft', 0],
+    [5, 'm', 'ft', 16.404],
+    [5, 'm', 'mi', 0.003],
+    [5, 'm', 'm', 5.0],
+    [5, 'm', 'km', 0.005],
+    [5, 'km', 'ft', 16404.199],
+    [5, 'km', 'mi', 3.107],
+    [5, 'km', 'm', 5000.0],
+    [5, 'km', 'km', 5.0],
+    [5, 'ft', 'ft', 5.0],
+    [5, 'ft', 'mi', 0.001],
+    [5, 'ft', 'm', 1.524],
+    [5, 'ft', 'km', 0.002],
+    [5, 'mi', 'ft', 26400.0],
+    [5, 'mi', 'mi', 5.0],
+    [5, 'mi', 'm', 8046.72],
+    [5, 'mi', 'km', 8.047],
+  ]
+
+  testsParams.map((testParams) => {
+    it(`convert ${testParams[0]}${testParams[1]} in ${testParams[2]}}`, () => {
+      assert.equal(
+        convertDistance(testParams[0], testParams[1], testParams[2]),
+        testParams[3]
+      )
+    })
+  })
+})
+
+describe('convertDistance w/ digits', () => {
+  const testsParams: [number, TUnit, TUnit, number | null, number][] = [
+    [5, 'km', 'mi', null, 3.106855961174243],
+    [5, 'km', 'mi', 0, 3],
+    [5, 'km', 'mi', 1, 3.1],
+    [5, 'km', 'mi', 2, 3.11],
+  ]
+
+  testsParams.map((testParams) => {
+    it(`convert ${testParams[0]}${testParams[1]} in ${testParams[2]}}`, () => {
+      assert.equal(
+        convertDistance(
+          testParams[0],
+          testParams[1],
+          testParams[2],
+          testParams[3]
+        ),
+        testParams[4]
+      )
+    })
+  })
+})