feat: add case helper

src/helpers/case.ts

@@ -0,0 +1,16 @@
+import { HandlebarsHelper, HelperConstructorBlock } from "./helper";
+
+export const caseHelper: HelperConstructorBlock = ctx => {
+    return new HandlebarsHelper("case", (type, rawV1): string => {
+        const v1 = new String(rawV1);
+
+        switch (type) {
+            case "upper":
+                return v1.toUpperCase();
+            case "lower":
+                return v1.toLowerCase();
+            default:
+                throw new Error(`Invalid case type used with case: ${type}`);
+        }
+    });
+};

src/helpers/index.ts

@@ -8,6 +8,7 @@ import { mathHelper } from "./math";
 import { conditionHelper } from "./condition";
 import { repeatHelper } from "./repeat";
 import { advancedDatetimeHelper } from "./advanced_datetime";
+import { caseHelper } from "./case";
 
 export class HelperFactory {
     private static helpers: HelperConstructorBlock[] = [
@@ -17,6 +18,7 @@ export class HelperFactory {
         conditionHelper,
         repeatHelper,
         advancedDatetimeHelper,
+        caseHelper,
     ];
 
     static registerHelpers(dateAndTimeUtils: DateAndTimeUtils): void {