add unit computation

ts/index.ts

@@ -2,3 +2,4 @@ import * as plugins from './smarttime.plugins'
 
 export * from './smarttime.classes.hrtmeasurement'
 export * from './smarttime.classes.timestamp'
+export * from './smarttime.units'

ts/smarttime.units.ts

@@ -0,0 +1,45 @@
+export let units = {
+  years: (timesArg = 1): number => {
+    return timesArg * 3154e+10
+  },
+  months: (timesArg = 1): number => {
+    return timesArg * 2628e+9
+  },
+  weeks: (timesArg = 1) => {
+    return timesArg * 6048e+8
+  },
+  days: (timesArg = 1) => {
+    return timesArg * 864e+7
+  },
+  hours: (timesArg = 1) => {
+    return timesArg * 36e+6
+  },
+  minutes: (timesArg = 1) => {
+    return timesArg * 60000
+  }
+}
+
+export interface IUnitCombinationArg {
+  years?: number
+  months?: number
+  weeks?: number
+  days?: number
+  hours?: number
+  minutes?: number
+}
+
+export let getMilliSecondsFromUnits = (combinationArg: IUnitCombinationArg) => {
+  let timeInMilliseconds = 0
+  let addMilliSeconds = (milliSecondsArg) => {
+    timeInMilliseconds = timeInMilliseconds + milliSecondsArg
+  }
+  if (combinationArg.years) { addMilliSeconds(units.years(combinationArg.years)) }
+  if (combinationArg.months) { addMilliSeconds(units.months(combinationArg.months)) }
+  if (combinationArg.weeks) { addMilliSeconds(units.weeks(combinationArg.weeks)) }
+  if (combinationArg.days) { addMilliSeconds(units.days(combinationArg.days)) }
+  if (combinationArg.hours) { addMilliSeconds(units.hours(combinationArg.hours)) }
+  if (combinationArg.minutes) { addMilliSeconds(units.minutes(combinationArg.minutes)) }
+
+  return timeInMilliseconds
+}
+