feat: support one to many & many to many relations

Author: mzalevski

index.test.ts

@@ -12,6 +12,11 @@ type Check = CheckBase & {
   place: PlaceBase;
 };
 
+type Place = PlaceBase & {
+  /** checks relation */
+  checks: Check[];
+};
+
 test("some fields, no relations & no omissions", () => {
   const shape = getShape<Check>()({
     id: true,
@@ -190,3 +195,19 @@ test("foreign fields & relations", () => {
     "id,place_id,user_id,place:place_id(id,title),user:user_id(id,name)"
   );
 });
+
+test("1:m and n:m relations", () => {
+  const shape = getShape<Place>()({
+    id: true,
+    checks: [{ id: true }],
+  });
+
+  expectType<{
+    id: string;
+    checks: { id: string }[];
+  }>(shape);
+
+  const fields = getFields(shape);
+
+  expect(fields).toBe("id,checks(id)");
+});

src/index.ts

@@ -1,7 +1,7 @@
 type MakePropTypesBoolean<T, A = T> = T extends object
   ? { [K in keyof T]: MakePropTypesBoolean<Partial<T[K]>, T> } & {
       /** which field to join by */
-      _: keyof A;
+      _?: keyof A;
       /** wheter to get all the fields */
       "*"?: true;
     }
@@ -13,6 +13,8 @@ type OmitFalseKeys<T> = {
 
 export type ParseReturnType<T, U> = U extends { "*": true }
   ? T
+  : U extends Array<infer UE>
+  ? ParseReturnType<T extends Array<infer TE> ? TE : T, UE>[]
   : U extends Record<string, unknown>
   ? Omit<
       {
@@ -76,7 +78,7 @@ export const getFields = (shape: Record<string, any>) => {
 
     return undefined;
   })
-    .replace(/[": \n]/g, "")
+    .replace(/[(": \n)(\[)(\])]/g, "")
     .replace(/\{/g, "(")
     .replace(/\}/g, ")")
     .slice(1, -1)}`;