Summing array of string numbers using JavaScript

Problem

We are required to write a JavaScript function that takes in an array that contains integers and string numbers.

Our function should sum all the integers and string numbers together to derive a new number and return that number.

Example

Following is the code ?

const arr = [67, 45, '34', '23', 4, 6, '6'];

const mixedSum = (arr = []) => {
    let sum = 0;
    for(let i = 0; i < arr.length; i++){
        const el = arr[i];
        sum += +el;
    };
    return sum;
};

console.log(mixedSum(arr));

Output

185

How It Works

The unary plus operator (+) converts string numbers to integers. When we write +el, JavaScript automatically converts the string '34' to the number 34.

console.log(+'34');    // 34 (number)
console.log(typeof +'34');  // "number"

34
number

Alternative Approaches

Using reduce() Method

const arr = [67, 45, '34', '23', 4, 6, '6'];

const mixedSumReduce = (arr = []) => {
    return arr.reduce((sum, current) => sum + (+current), 0);
};

console.log(mixedSumReduce(arr));

185

Using Number() Constructor

const arr = [67, 45, '34', '23', 4, 6, '6'];

const mixedSumNumber = (arr = []) => {
    let sum = 0;
    for(const element of arr){
        sum += Number(element);
    }
    return sum;
};

console.log(mixedSumNumber(arr));

185

Comparison

Conclusion

The unary plus operator provides the fastest way to convert string numbers to integers for summation. All three approaches handle mixed arrays effectively, with reduce() offering the most functional programming style.