Add difference helper

packages/string-templates/src/helpers/date.ts

@@ -1,4 +1,4 @@
-import dayjs from "dayjs"
+import dayjs, { UnitType } from "dayjs"
 
 import dayjsDurationPlugin from "dayjs/plugin/duration"
 import dayjsAdvancedFormatPlugin from "dayjs/plugin/advancedFormat"
@@ -133,3 +133,8 @@ export const duration = (str: any, pattern: any, format: any) => {
     return duration.humanize()
   }
 }
+
+export const difference = (from: string, to: string, units: UnitType) => {
+  const result = dayjs(new Date(from)).diff(dayjs(new Date(to)), units)
+  return result
+}

packages/string-templates/src/helpers/external.ts

@@ -1,7 +1,7 @@
 // @ts-ignore we don't have types for it
 import helpers from "@budibase/handlebars-helpers"
 
-import { date, duration } from "./date"
+import { date, difference, duration } from "./date"
 import {
   HelperFunctionBuiltin,
   EXTERNAL_FUNCTION_COLLECTIONS,
@@ -9,8 +9,9 @@ import {
 import Handlebars from "handlebars"
 
 const ADDED_HELPERS = {
-  date: date,
-  duration: duration,
+  date,
+  duration,
+  difference,
 }
 
 export const externalCollections = EXTERNAL_FUNCTION_COLLECTIONS