Merge pull request #14650 from RickCarlino/later

Add strictNullCheck compatibility to LaterJS typings. Fixes #14646

later/index.d.ts

@@ -142,7 +142,7 @@ declare namespace later {
          * For acces to custom time periods created as extension to the later static type
          * and modifiers created on the later modifier static type.
          */
-        [ timeperiodAndModifierName: string ]: number[];
+        [ timeperiodAndModifierName: string ]: number[] | undefined;
     }
 
     interface ParseStatic {

later/tsconfig.json

@@ -7,7 +7,7 @@
         ],
         "noImplicitAny": true,
         "noImplicitThis": true,
-        "strictNullChecks": false,
+        "strictNullChecks": true,
         "baseUrl": "../",
         "typeRoots": [
             "../"