JSFiddle - React, Tailwind, and code Playground

JavaScript

function sumofArr(arr){ // here i create a function that has one argument called arr
var total = 0; // I initialize a variable and set it equal to 0 
var str = "12sf0as9d" // this is the string where I want to add only integers
var patrn = "\\D"; // this is the regular expression that removes the letters
var tot = str.split(patrn) // here i add split the string and store it into an array with my pattern

arr.forEach(function(tot){ // I use a forEach loop to iterate over the array 
total += parseInt(tot); // add the previous total to the new total
})
return total; // return the total once finished
}

alert(sumofArr(["1", "2", "3"]));