Fix MapExtended when literal array was provided. Add PageToObject function to fix issue in MapExtended when an actual page was provided

Author: eigilsagafos

src/fql-lib.ts

@@ -1,4 +1,5 @@
 export { MapExtended } from "./functions/MapExtended"
 export { ObjectKeys } from "./functions/ObjectKeys"
+export { PageToObject } from "./functions/PageToObject"
 export { PaginateReverse } from "./functions/PaginateReverse"
 export { Reverse } from "./functions/Reverse"

src/functions/MapExtended.ts

@@ -1,16 +1,18 @@
-import { query as q, ExprArg, Lambda } from "faunadb"
+import { query as q, ExprArg, Lambda, ExprVal } from "faunadb"
+import { PageToObject } from "./PageToObject"
 
 export const MapExtended = (
     collection: ExprArg,
     lambdaExpr: ExprArg | Lambda
-) =>
-    q.If(
+): ExprVal => {
+    return q.If(
         q.IsArray(collection),
-        q.Map(q.Select(["data"], collection), lambdaExpr),
+        q.Map(collection, lambdaExpr),
         q.Let(
             {
                 data: q.Map(q.Select(["data"], collection), lambdaExpr),
             },
-            q.Merge(collection, { data: q.Var("data") })
+            q.Merge(PageToObject(collection), { data: q.Var("data") })
         )
     )
+}

src/functions/PageToObject.ts

@@ -0,0 +1,17 @@
+import { query as q, ExprArg, ExprVal } from "faunadb"
+
+export const PageToObject = (page: ExprArg): ExprVal =>
+    /*
+        Is this a bug? Using as a feature in this case.
+        q.Merge({}, { foo: null })            // => {}
+        q.Merge({foo: null }, { foo: null })  // => {}
+        q.Merge({foo: null }, {})             // => { foo: null }
+    */
+    q.Merge(
+        {},
+        {
+            before: q.Select(["before"], page, null),
+            after: q.Select(["after"], page, null),
+            data: q.Select(["data"], page),
+        }
+    )