Merge to main

README.md

@@ -103,7 +103,7 @@ export interface JoinDataParam {
   local: LocalParam;
 
   /**
-   * Object(s) or an asynchronous callback function that returns the data from the source.
+   * Objects or an asynchronous callback function that returns the data from the source.
    */
   from: FromParam;
 
@@ -128,9 +128,10 @@ export interface JoinDataParam {
   asMap?: AsMap;
 }
 
+export type LocalParam = object | object[];
+
 export type FromParam =
-  | ((localFieldValues: Primitive[], metadata: any) => any)
-  | object
+  | ((localFieldValues: Primitive[], metadata: any) => object[])
   | object[];
 
 export type AsMap =
@@ -146,15 +147,15 @@ The join method in `@objectwow/join` offers better performance compared to the j
 ### Traditional Approach (Database, Krakend, Hasura, GraphQL):
 
 1. Loop through the original array.
-2. `For each element, make a call` to the table/service containing the related data by its ID.
+2. `For each element, make a call` to the `database/internal/external service` containing the related data by its `UID` (unique identifier).
 3. Combine the data from both sources.
 4. This results in a time complexity of `O(n x m)`, where `n` is the number of elements in the original array, and `m` is the number of elements fetched from the related table or service.
 
 ### @objectwow/join Approach:
 
-1. Provides a `callback function` where the input is `an array of IDs`, allowing the developer to fetch related data from the table/service in a `single call`.
-2. Uses JavaScript’s `new Map` to optimize the process, reducing the time complexity from O(m) to O(1), where m is the number of elements retrieved..
-3. Combines the data efficiently after retrieving it in bulk through a `single call`.
+1. Provides a `callback function` where the input is `UIDs`, allowing the developer to fetch related data from the `database/internal/external service` in a `single call`.
+2. Uses JavaScript’s `new Map` to optimize the process, reducing the time complexity from O(m) to O(1), where `m` is the number of elements retrieved..
+3. Combines the data efficiently after retrieving it in bulk through a single call.
 4. This results in a time complexity of O(n), where `n` is the number of elements in the original array.
 
 By fetching related data in bulk and leveraging efficient JavaScript data structures, `@objectwow/join` minimizes redundant calls and improves overall performance.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@objectwow/join",
-  "version": "0.2.5",
+  "version": "0.3.0",
   "license": "MIT",
   "description": "Join objects with functionality similar to MongoDB's $lookup",
   "publishConfig": {

src/core.ts

@@ -244,18 +244,22 @@ export class JoinData {
     metadata?: any
   ): Promise<any[]> {
     if (typeOf(from) === Types.Object) {
-      return [from];
+      throw new Error("from must be an array of objects");
     }
 
     if (typeOf(from) === Types.Array) {
-      return from as any[];
+      return from as object[];
     }
 
-    const result = await (from as Function)(localFieldValues, metadata);
-    const fromArr =
-      typeOf(result) === Types.Array ? (result as object[]) : [result];
+    if (typeOf(from) === Types.Function) {
+      const result = await (from as Function)(localFieldValues, metadata);
 
-    return fromArr;
+      if (typeOf(result) === Types.Array) {
+        return result as object[];
+      }
+    }
+
+    throw new Error("from must be an array of objects");
   }
 
   protected generateResult(

src/type.ts

@@ -5,8 +5,7 @@ export type LocalValue = any | any[];
 export type LocalParam = object | object[];
 
 export type FromParam =
-  | ((localFieldValues: Primitive[], metadata: any) => any)
-  | object
+  | ((localFieldValues: Primitive[], metadata: any) => object[])
   | object[];
 
 export type AsMap =
@@ -24,7 +23,7 @@ export interface JoinDataParam {
   local: LocalParam;
 
   /**
-   * Object(s) or an asynchronous callback function that returns the data from the source.
+   * Objects or an asynchronous callback function that returns the data from the source.
    */
   from: FromParam;
 

tests/core.spec.ts

@@ -69,7 +69,7 @@ describe("JoinData - execute method full coverage", () => {
     ];
 
     const param: JoinDataParam = {
-      from: fromFn,
+      from: await fromFn(),
       local: [{ id: 1 }, { id: 2 }],
       localField: "id",
       fromField: "id",
@@ -98,7 +98,7 @@ describe("JoinData - execute method full coverage", () => {
     ];
 
     const param: JoinDataParam = {
-      from: fromFn,
+      from: await fromFn(),
       local: [{ id: 1 }, { id: 2 }],
       localField: "id",
       fromField: "id",
@@ -164,7 +164,7 @@ describe("JoinData - execute method full coverage", () => {
       { id: 2, items: [101, 201] },
     ];
 
-    const from = async () => [
+    const from = () => [
       { id: 101, product: "Product 101" },
       { id: 102, product: "Product 102" },
       { id: 201, product: "Product 201" },

tests/singleton.spec.ts

@@ -33,24 +33,4 @@ describe("SingletonJoinData and joinData", () => {
       expect(instance1).not.toBe(instance2);
     });
   });
-
-  describe("joinData function", () => {
-    it("should call the execute method of the JoinData instance with the correct parameters", async () => {
-      const params: JoinDataParam = {
-        from: () => ({}),
-        local: {},
-        localField: "id",
-        fromField: "foreignId",
-        as: "result",
-      };
-
-      const expectedResult: JoinDataResult = {
-        joinFailedValues: [],
-        allSuccess: true,
-      };
-
-      const result = await joinData(params);
-      expect(result).toEqual(expectedResult);
-    });
-  });
 });