Merge pull request #3672 from openstax/fix/interval

use whole numbers and read as sentence

shared/specs/model/time.spec.ts

@@ -58,12 +58,12 @@ describe('time class', () => {
     })
 
     it('converts to interval with human display', () => {
-        const past = new Time('2021-01-15T10:00:00.000Z')
-        const future = new Time('2021-01-15T10:58:00.000Z')
+        const past = new Time('2021-01-14T03:00:00.000Z')
+        const future = new Time('2021-01-15T10:58:03.330Z')
         const interval = future.intervalTo(past)
         // it flipped start/end so start always comes first
         expect(interval.start.isSame(past, 'millisecond')).toBe(true)
-        expect(interval.humanized).toEqual('58 minutes')
+        expect(interval.humanized).toEqual('1 day, 7 hours and 58 minutes')
     })
 
 })

shared/src/model/time.ts

@@ -9,6 +9,7 @@ import moment from 'moment';
 import { extendMoment } from 'moment-range';
 import pluralize from 'pluralize';
 import { now as getNow } from 'mobx-utils'
+import { toSentence } from '../helpers/string';
 
 const { range } = extendMoment(moment as any);
 
@@ -188,12 +189,12 @@ export class Interval {
     }
 
     get humanized() {
-        const { days, hours, minutes } = this.asLuxon.toDuration(['days', 'hours', 'minutes'])
+        const { days, hours, minutes } = this.asLuxon.toDuration(['days', 'hours', 'minutes', 'seconds'])
         let str: string[] = []
         if (days)  str.push(pluralize('day', days, true))
         if (hours) str.push(pluralize('hour', hours, true))
         if (minutes) str.push(pluralize('minute', minutes, true))
-        return str.join(' ')
+        return toSentence(str)
     }
 
     get asMoment() {