How to extract last digit from string which contains chars and numbers

Question

How can i extract from string only last number which should be "5"?

var str = "1000040928423195 points added to your balance";
var str = parseInt(str);
var lastNum = str.substr(str.length - 1);
console.log(lastNum);

Answer 1

Given your string...

var str = "1000040928423195 points added to your balance";

... we can extract all the numbers with a regex...

var onlyNumbers = str.replace(/\D/g,'');

... and, finally, get the last one:

var lastNumber = onlyNumbers.substring(onlyNumbers.length - 1);

Here is a demo:

var str = "1000040928423195 points added to your balance";
var onlyNumbers = str.replace(/\D/g,'');
var lastNumber = onlyNumbers.substring(onlyNumbers.length - 1);

console.log(lastNumber);