script.js

// This is the forEach() Function
function myEach(arr, func) {
  for (let i = 0; i < arr.length; i++) {
    func(arr[i]);
  }
}

let forEachArray = [1, 3, 5];

myEach(forEachArray, function(num){
  console.log(num);
});


//This is the map() function
function myMap(arr, func) {
  let result = [];
  for (let i = 0; i < arr.length; i++) {
    result.push(func(arr[i]));
  }
  return result;
}

let mapArray = [2,7,6,3];

let doubleNumber = myMap(mapArray, function(num){
 return num * 2 ;
});

console.log(doubleNumber);

//This is the filter() function
function myFilter(arr, func){
    let result = [];
    for (let i = 0; i < arr.length ; i++){
         if (func(arr[i])){
            result.push(arr[i]);
        }
    }
    return result;

}

let filterArray = [2,7,6,3];

let evenNumbers = myFilter(filterArray, function (num){
    return num % 2 === 0;
});

console.log(evenNumbers);

//This is the some() (aka any()) function
function mySome(arr, func){
    for (let i = 0; i < arr.length ; i++){
         if (func(arr[i])){
          return true;
        }
    }
    return false;

}

let someArray = [7,3,5,9];

let hasEvenNumber = mySome(someArray, function(num){
    return num % 2 === 0;
});

console.log(hasEvenNumber);

//This is the every() function
function myEvery(arr, func){
    for (let i = 0; i < arr.length ; i++){
         if (func(arr[i])){
          return false;
        }
    }
    return true;
};

let everyArray = [2,6,8,12];

let hasAllEvenNumber = myEvery(everyArray, function(num){
    return num % 2 !== 0;
});

console.log(hasAllEvenNumber);

//This is the reduce() function
function myReduce(arr, func){
    let add = 0
    for (let i = 0; i < arr.length ; i++){
         add = func(add, arr[i]);
        }
          return add;
    }

let reduceArray = [2,6,8,12];

let sum = myReduce(reduceArray, function(acc, num){
    return acc + num;
});

console.log(sum);

//This is the includes() function
function myIncludes(arr, func){
    for (let i = 0; i < arr.length ; i++){
         if (func (arr[i]))
            return true;
        }
         return false;
    }

let fruits = ['apple', 'banana', 'orange', 'grape'];

let hasBanana = myIncludes(fruits, function(fruit){
    return fruit === 'banana';
})

console.log(hasBanana);

//This is the indexOf() Function
function myIndexOf(arr, func){
    for (let i = 0; i < arr.length ; i++){
         if (func (arr[i]))
            return i;
        }
         return -1;
}

//let fruits = ['apple', 'banana', 'orange', 'grape'];

let hasFruit = myIndexOf(fruits, function(fruit){

    return  fruit === 'orange';

})

console.log(hasFruit);

hasFruit = myIndexOf(fruits, function(fruit){

    return  fruit === 'pear';
})

console.log(hasFruit);


//This is the function for push()
function myPush(arr, addition){
    arr[arr.length] = addition;
    return arr.length;
}

//let fruits = ['apple', 'banana', 'orange', 'grape']
let length = myPush(fruits, 'orange');
console.log(fruits);
console.log(length);


//This is the function for lastIndexOf()
function myUnShift(arr, target) {
  for (let i = arr.length - 1; i >= 0; i--) {
    if (arr[i] === target) {
      return i;
    }
  }
  return -1;
}
const animals = ['cat', 'dog', 'bird', 'dog', 'fish'];

const lastIndexDog = myUnShift(animals, 'dog');
console.log(lastIndexDog); // 3

const lastIndexCow = myUnShift(animals, 'cow');
console.log(lastIndexCow); // -1



//This is the function for Object.keys()
function grabKeys(obj) {
  let keys = [];
  for (let key in obj) {
    if (obj.hasOwnProperty(key)) {
      keys.push(key);
    }
  }
  return keys;
}
const student = {
  firstname: 'John',
  lastname: 'Doe',
  age: 22,
  gender: 'male'
};
const keys = grabKeys(student);
console.log(keys);


//This is the Object.values()
function grabValues(obj) {
  let values = [];
  for (let key in obj) {
    if (obj.hasOwnProperty(key)) {
      values.push(obj[key]);
    }
  }
  return values;
}

const car = {
  make: 'Toyota',
  model: 'Corolla',
  year: 2020
};

const value = grabValues(car);
console.log(value);