Question

// ==== Challenge 1: Write your own closure ====

// Write a closure of your own creation.

// Keep it simple! Remember a closure is just a function

// that manipulates variables defined in the outer scope.

// The outer scope can be a parent function, or the top level of the script.

/* STRETCH PROBLEMS, Do not attempt until you have completed all previous tasks for today's project files */

// ==== Challenge 2: Implement a "counter maker" function ====

const counterMaker = () => {

// IMPLEMENTATION OF counterMaker:

// 1- Declare a `count` variable with a value of 0. We will be mutating it, so declare it using `let`!

// 2- Declare a function `counter`. It should increment and return `count`.

// NOTE: This `counter` function, being nested inside `counterMaker`,

// "closes over" the `count` variable. It can "see" it in the parent scope!

// 3- Return the `counter` function.

};

// Example usage: const myCounter = counterMaker();

// myCounter(); // 1

// myCounter(); // 2

// ==== Challenge 3: Make `counterMaker` more sophisticated ====

// It should have a `limit` parameter. Any counters we make with `counterMaker`

// will refuse to go over the limit, and start back at 1.

// ==== Challenge 4: Create a counter function with an object that can increment and decrement ====

const counterFactory = () => {

// Return an object that has two methods called `increment` and `decrement`.

// `increment` should increment a counter variable in closure scope and return it.

// `decrement` should decrement the counter variable and return it.

};

Answer 1

If you have any doubt with the programs feel free to comment

Challenge 1

            function bmiCal(weight, height) {

                bmi = weight / (height * height);//calculating bmi

                bmi = bmi.toFixed(2);//limiting to decimal place

                return  function () {//using the power of closure to use the variable bmi

                    //checking bmi and health status

                    if (bmi <= 18.5)

                        return "BMI: " + bmi + " Index: " +"Thin";

                    else if (bmi >= 18.6 && bmi <= 24.9)

                        return "BMI: " + bmi + " Index: " +"Healthy";

                    else if (bmi >= 25 && bmi <= 29.9)

                        return "BMI: " + bmi + " Index: " +"Overweight";

                    else

                        return "BMI: " + bmi + " Index: " +"Obese";

                };

            }

            //weight in kg and height in meters

            console.log(bmiCal(60, 1.66)());//calling bmiCal() and retrun anonymous function

Challenge 2 & 3

    //challenge 2 & 3

    const counterMaker = (limit) => {

        let count =0;

        function counter(){

            count++;//increasing count

            if(count > limit){//checking limit

                count = 1;

                return count;

            }

            else{

                return count;

            }

        }

        return counter;

    }

    const myCounter = counterMaker(5);//limit is 5

    console.log(myCounter());// 1

    console.log(myCounter());// 2

    console.log(myCounter());// 3

    console.log(myCounter());// 4

    console.log(myCounter());// 5

    console.log(myCounter());// 1

Challenge 4

    //challenge 4

    const counterFactory = () => {

        let count =0;

        return  {

            increment : function(){//creating increament object

                return ++count;//increasing count

            },

            decrement: function(){//creating decreament object

                return --count;//decreasing object

            }

        }

    }

    //showing output

    const myCounter = counterFactory();

    console.log(myCounter.increment());

    console.log(myCounter.decrement());