fix isEmpty bug with bigInt

src/danfojs-base/shared/utils.ts

@@ -86,12 +86,25 @@ export default class Utils {
     }
 
     /**
-     * Checks if a value is empty. Empty means it's either null, undefined or NaN
+     * Checks if a value is empty. Empty means it's either null, undefined or NaN.
+     * Empty strings are NOT considered empty.
      * @param value The value to check.
-     * @returns 
+     * @returns boolean indicating if the value is empty
      */
     isEmpty<T>(value: T): boolean {
-        return value === undefined || value === null || (isNaN(value as any) && typeof value !== "string");
+        if (value === undefined || value === null) {
+            return true;
+        }
+
+        if (typeof value === 'bigint') {
+            return false; // BigInt values are never considered empty
+        }
+
+        if (typeof value === 'number') {
+            return isNaN(value);
+        }
+
+        return false; // All other types (strings, objects, arrays, etc) are not considered empty
     }
 
     /**

src/danfojs-node/test/utils.test.ts

@@ -40,6 +40,49 @@ describe("Utils", function () {
         assert.isTrue(utils.isUndefined(arr));
     });
 
+    describe("isEmpty", function () {
+        it("should return true for null values", function () {
+            assert.isTrue(utils.isEmpty(null));
+        });
+
+        it("should return true for undefined values", function () {
+            assert.isTrue(utils.isEmpty(undefined));
+        });
+
+        it("should return true for NaN values", function () {
+            assert.isTrue(utils.isEmpty(NaN));
+        });
+
+        it("should return false for strings (including empty strings)", function () {
+            assert.isFalse(utils.isEmpty(""));
+            assert.isFalse(utils.isEmpty("   "));
+            assert.isFalse(utils.isEmpty("hello"));
+        });
+
+        it("should return false for numbers (except NaN)", function () {
+            assert.isFalse(utils.isEmpty(0));
+            assert.isFalse(utils.isEmpty(-1));
+            assert.isFalse(utils.isEmpty(42.5));
+        });
+
+        it("should return false for BigInt values", function () {
+            assert.isFalse(utils.isEmpty(BigInt(9007199254740991)));
+            assert.isFalse(utils.isEmpty(BigInt(0)));
+        });
+
+        it("should return false for objects and arrays", function () {
+            assert.isFalse(utils.isEmpty({}));
+            assert.isFalse(utils.isEmpty([]));
+            assert.isFalse(utils.isEmpty({ key: "value" }));
+            assert.isFalse(utils.isEmpty([1, 2, 3]));
+        });
+
+        it("should return false for boolean values", function () {
+            assert.isFalse(utils.isEmpty(true));
+            assert.isFalse(utils.isEmpty(false));
+        });
+    });
+
     it("Checks if value is a valid Date object", function () {
         let date1 = new Date();
         let date2 = "2021-01-01 00:00:00";