fix(core): allow shuffle to return first element in first index (#3070)

Author: gracetxgao

libs/core/src/utils/shuffle.spec.ts

@@ -11,4 +11,16 @@ describe('Core | Utils | shuffle', () => {
     });
     expect(initialArray).not.toEqual(result);
   });
+
+  it('should return array containing the same single element if input contains one element', () => {
+    const initialArray = [1];
+    const result = shuffle(initialArray);
+    expect(initialArray).toEqual(result);
+  });
+
+  it('should return an empty array if input is an empty array', () => {
+    const initialArray = [];
+    const result = shuffle(initialArray);
+    expect(initialArray).toEqual(result);
+  });
 });

libs/core/src/utils/shuffle.ts

@@ -5,7 +5,7 @@
 export const shuffle = <T>(array: T[]): T[] => {
   const result = [];
   array.forEach((el, i) => {
-    const s = Math.floor(Math.random() * i);
+    const s = Math.floor(Math.random() * (i + 1));
     if( s !== i ){
       result[i] = result[s];
     }