feat: Add Type checking when using morphism currying function

Author: emyann

src/morphism.ts

@@ -248,7 +248,8 @@ const getSchemaForType = (type: any, baseSchema: any) => {
  * @param  {} type
  *
  */
-export function morphism(schema: Schema, items?: any, type?: any): typeof type;
+export function morphism<TSource, TSchema extends Schema>(schema: TSchema, items?: TSource[]): TSchema[]; // m({},[]) => {}[]
+export function morphism<TSource, TSchema extends Schema>(schema: TSchema, items?: TSource): TSchema; // m({},{}) => {}
 
 export function morphism(schema: Schema, items?: any, type?: any): typeof type {
   if (items === undefined && type === undefined) {

src/typings.spec.ts

@@ -0,0 +1,19 @@
+import Morphism, { morphism, Schema } from './morphism';
+
+describe('Morphism', () => {
+  describe('Currying Function overload', () => {
+    it('Should return a collection of objects when an array is provided as source', () => {
+      const schema = { foo: 'bar' };
+      const res: { foo: string }[] = morphism(schema, [{ bar: 'test' }]);
+
+      expect(res.map).toBeDefined();
+      expect(res[0].foo).toEqual('test');
+    });
+    it('Should return a single object matching the schema structure when an object is provided as source', () => {
+      const schema = { foo: 'bar' };
+      const res: { foo: string } = morphism(schema, { bar: 'test' });
+
+      expect(res.foo).toEqual('test');
+    });
+  });
+});