Odtnhj

I need to sum all numbers 1 from a string!

For example: "00110010" = 1+1+1 = 3...

psum will receive this result and then I will check

if(psum >= 3)
 return person;

I need to find a way to solve it in javascript ES6 but I can't use any for, while or forEach loop, unfortunately!!!

Could you help me?

You need to use the reduce() method.

let input = '00110010'
let array = input.split("").map(x => parseInt(x));

let sum = array.reduce((acc, val) => 
 return acc + val;
);

console.log(sum)

In one statement:

let psum = "00110010".split('').reduce((t, n) => return t + parseInt(n), 0);

console.log(psum);

Note that summing the numbers 1 comes down to counting the numbers 1, which is what the following solutions do in different ways:

With match

You could use a regular expression /1/g:

var p = "00110010";
var psum = (p.match(/1/g) || ).length;

console.log(psum);

match returns an array of substrings that match with the pattern 1. The / just delimit this regular expression, and the g means that all matches should be retrieved (global). The length of the returned array thus corresponds to the number of 1s in the input. If there are no matches at all, then match will return null, so that does not have a .length property. To take care of that || will check for that null (which is falsy in a boolean expression) and so will be taken instead of null.

With replace

This is a similar principle, but by matching non-1 characters and removing them:

var p = "00110010";
var psum = p.replace(/[^1]/g, "").length;

console.log(psum);

[^1] means: a character that is not 1. replace will replace all matches with the second argument (empty string), which comes down to returning all characters that do not match. This is like a double negative: return characters that do not match with not 1. So you get only the 1s :-) .length will count those.

With split:

var p = "00110010";
var psum = p.split("1").length - 1;

console.log(psum);

split splits the string into an array of substrings that do not have the given substring ("1"). So even if there are no "1" at all, you get one such substring (the whole string). This means that by getting the length, we should reduce it by 1 to get the number of 1s.

With a recursive function:

var p = "00110010";
var count1 = p => p.length && ((p[0] == "1") + count1(p.slice(1)));
var psum = count1(p);

console.log(psum);

Here the function count1 is introduced. It first checks if the given string p is empty. If so, length is zero, and that is returned. If not empty, the first character is compared with 1. This can be false or true. This result is converted to 0 or 1 respectively and added to a recursive call result. That recursive call counts the number 1s in the rest of the input (excluding the first character in which the 1s were already counted).