fixed flattenObject

index.html

@@ -97,7 +97,7 @@ <h4>Data Pipe testing page. Do not expect anything here! </h4>
     }
 
     function onButtonClick() {
-      const data = [{ a: 1, d:{d1:22, d2:33} }, { b: 2, d:{d1:221, d2:331} }];
+      const data = [{ a: null, d:{d1:22, d2:33} }, { b: 2, d:{d1:221, d2:331, d3: null} }];
       console.log('* fieldsInfo => ', dp.dataPipe(data).flattenObject());
       // const json = `[{"value":"test value\\\\d"}]`;
       // console.log(json)

package.json

@@ -1,6 +1,6 @@
 {
     "name": "datapipe-js",
-    "version": "0.3.28",
+    "version": "0.3.29",
     "description": "dataPipe is a data processing and data analytics library for JavaScript. Inspired by LINQ (C#) and Pandas (Python)",
     "main": "dist/cjs/data-pipe.js",
     "module": "dist/esm/data-pipe.mjs",

src/array/transform.ts

@@ -44,16 +44,33 @@ export function distinct(array: any[], elementSelector?: Selector): any[] {
   }
   return Array.from(new Set(array));
 }
-
+/**
+ * Flatten Object or array of objects
+ * Object 
+ * [{ a: 1, d:{d1: 22, d2: 33} }, { b: 2, d:{d1:221, d2:331} }]
+ * will become
+ * [{ a: 1, d.d1: 22, d.d2: 33 }, { b: 2, d.d1: 221, d.d2: 331 }]
+ * @param data 
+ * @returns 
+ */
 export function flattenObject(data: any): any {
+  if (!data || typeof data !== 'object') {
+    return data;
+  }
+
   function iterate(rootData: any, obj: any, prefix: string): void {
     const keys = Object.keys(rootData);
 
     for (let i = 0; i < keys.length; i++) {
-      const pName = prefix? `${prefix}.${keys[i]}`: keys[i];
+      const pName = prefix ? `${prefix}.${keys[i]}` : keys[i];
 
       const value = rootData[keys[i]];
-      if (typeof value === 'object' && !(value instanceof Date)) {
+      if (
+        typeof value === 'object' &&
+        value !== null &&
+        value !== undefined &&
+        !(value instanceof Date)
+      ) {
         iterate(value, obj, pName);
       } else if (typeof value === 'function') {
         continue;