added some challenging datagit add .git add .!

Author: ashish8513

ArrReduce.js

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+// Given an integer array nums, a reducer function fn, and an initial value init, return the final result obtained by executing the fn function on each element of the array, sequentially, passing in the return value from the calculation on the preceding element.
+
+// This result is achieved through the following operations: val = fn(init, nums[0]), val = fn(val, nums[1]), val = fn(val, nums[2]), ... until every element in the array has been processed. The ultimate value of val is then returned.
+
+// If the length of the array is 0, the function should return init.
+
+// Please solve it without using the built-in Array.reduce method.
+
+var reduce = function (nums, fn, init) {
+    let val = init;
+    if (nums.length === 0) {
+        return init
+    } else {
+        nums.forEach((num) => {
+            val = fn(val, num)
+        })
+    }
+    return val;
+};

Array.js

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+// Given an integer array arr and a mapping function fn, return a new array with a transformation applied to each element.
+
+// The returned array should be created such that returnedArray[i] = fn(arr[i], i).
+
+// Please solve it without the built-in Array.map method.
+
+var map = function (arr, fn) {
+    var result = [];
+    arr.forEach((value, index) => {
+        result.push(fn(value, index));
+    })
+    return result
+}

Counter!!.js

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+// Write a function createCounter. It should accept an initial integer init. It should return an object with three functions.
+
+// The three functions are:
+
+// increment() increases the current value by 1 and then returns it.
+// decrement() reduces the current value by 1 and then returns it.
+// reset() sets the current value to init and then returns it.
+
+var createCounter = function (init) {
+    let currrentValue = init
+    return {
+        increment: () => {
+            return ++currrentValue;
+        },
+        decrement: () => {
+            return --currrentValue;
+        },
+        reset: () => {
+            currrentValue = init;
+            return currrentValue;
+        }
+    }
+}

FilterArray.js

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+// Given an integer array arr and a filtering function fn, return a filtered array filteredArr.
+
+// The fn function takes one or two arguments:
+
+// arr[i] - number from the arr
+// i - index of arr[i]
+// filteredArr should only contain the elements from the arr for which the expression fn(arr[i], i) evaluates to a truthy value. A truthy value is a value where Boolean(value) returns true.
+
+// Please solve it without the built-in Array.filter method.
+
+
+// ! the filter function is with the For Loop method
+/*var filter=function(arr,fn){
+    var filteredArr=[];
+    for(var i=0;i<arr.length;i++){
+        if(fn(arr[i],i)){
+            filteredArr.push(arr[i]);
+        }
+    }
+    return filteredArr;
+}*/
+// ? the filter function is with the ForEach  method
+var filter = function (arr, fn) {
+    let newArr = []
+    arr.forEach((value, index) => {
+        if (fn(value, index)) {
+            newArr.push(value);
+        }
+    })
+    return newArr;
+}

ToBe.js

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+function expect(val){
+    return {
+        toBe:(value)=>{
+            if(value===val){
+                return true;
+            }else{
+                throw "Not Equal";
+            }
+        },
+        notToBe:(value)=>{
+            if(value !== val){
+                return true;
+            }else{
+                throw "Equal "
+            }
+        }
+
+    }
+}
+const result =expect(5).toBe(5)
+console.log(result)

counter.js

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+function createCounter(n) {
+    let count = n;
+    return function () {
+        return count++;
+    }
+}
+
+const counter = createCounter(10);
+const result = [
+    counter(),
+    counter(),
+    counter()
+]
+console.log(result)

helloWorld.js

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+function createHellowWorld() {
+    return function () {
+        return "hello world";
+    }
+}
+const helloWorld=createHellowWorld();
+console.log(helloWorld())