CODEWITHSUNDEEP
javascriptclosures
user6488504
user6488504

Reputation:

JavaScript Closures: Add the numbers of an array by calling the inner function

I have an array with random numbers. I want to add the sum of these numbers by using calling the inner function using the outer function. Basically, using closures.

let arr = [93, 95, 88, 0, 55, 91];

let addMany = function(arr){
    let addTwo = function (numbers) {
        console.log('array', arr)
        console.log('numbers', numbers)

        return numbers.reduce((acc,cur) => acc+cur,0)
    }
    return addTwo(arr);
}
let sum = new addMany(arr);
console.log('final sum', sum)

let res = sum.addTwo();

console.log(res);

I also think I am passing array 'arr' bit too many times. I could be wrong.

I have already tried it using IIFE and modular approach. That one worked fine. I am trying to achieve the same this way.

Upvotes: 1

Views: 67

Answers (2)

Nina Scholz
Nina Scholz

Reputation: 386680

You could take a instanciable function and a prototype for adding the values.

function Numbers(array) {
    this.numbers = array;
}

Numbers.prototype.add = function () {
    return this.numbers.reduce((a, b) => a + b, 0);
};

var array = [93, 95, 88, 0, 55, 91],
    numbers = new Numbers(array),
    result = numbers.add();

console.log(result);

An other possibillity is to use a fluent interface, where you return an object with some functions, where you can chain the functions.

function take(array) {
    var object = {
            add: () => array.reduce((a, b) => a + b, 0),
            update: cb => take(array.map(cb)),
            valueOf: () => array
        };
    return object;
}

var array = [93, 95, 88, 0, 55, 91],
    numbers = take(array),
    result = numbers.add();

console.log(result);
console.log(numbers.valueOf());
console.log(numbers.update(x => 2 * x).valueOf());

Upvotes: 1

Jonas Wilms
Jonas Wilms

Reputation: 138427

With return addTwo(arr) you are already returning the result directly. I assume you rather want to return addTwo itself, and use arr inside addTwo:

let addMany = function(arr){
  let addTwo = function () {
    console.log('array', arr)
    return arr.reduce((acc,cur) => acc+cur,0)
  };
  return addTwo;
}

The you'd call it as:

 const closured = addMany(1, 2, 3);
 console.log(closured()); // call addTwo

In your example you are calling it as (new addMany(...)).addTwo() ... to achieve that behaviour, remove the return as constructors do not return anything, amd assign addTwo as a method to this (which is the returned object):

let addMany = function(arr){
  this.addTwo = function () {
    console.log('array', arr);

    return arr.reduce((acc,cur) => acc+cur,0)
  };
}

Upvotes: 1

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