created flatten Function

flatten.js

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+// Flattens a nested array (the nesting can be to any depth).
+// Hint: You can solve this using recursion.
+// Example: flatten([1, [2], [3, [[4]]]]); => [1, 2, 3, 4];
+
+
+
+function flatten(elements,level) {
+
+
+    let flattenArr=[];
+    let depth=level;
+
+     if(level===true){
+        depth=1;
+     }
+
+  /*approach:-
+  we will iterate over array and will check if any element of array is array or not 
+  if we get any element that is array so we will again call flatten function and pass that element
+   when it will return array as result so we will store into flatternArr using spread operator
+ */ 
+
+    for(let index=0;index<elements.length;index++){
+
+        //for checking if any element is array or not , we will use isArray method
+
+        if(Array.isArray(elements[index]) && depth>0){
+            // console.log('Arr: ',elements[index]);
+          flattenArr.push(...flatten(elements[index],depth-1));
+        }
+        else{
+            // console.log('element:',elements[index]);
+            flattenArr.push(elements[index]);
+        }
+    }
+ return flattenArr;
+}
+
+
+module.exports=flatten;
+

test/testFlatten.js

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+const flattenFunc=require('../flatten');
+
+let arr=[1,2,[4,[5,6,[8,9,10]]],5,[6,7]];
+
+let flattenArr=flattenFunc(arr,true);
+
+console.log('Flatten Array of depth-1: ',flattenArr);
+
+flattenArr=flattenFunc(arr,2);
+
+console.log('Flatten Array of depth-2: ',flattenArr);