Finding life path number based on a date of birth in JavaScript

Life Path Number

A person's Life Path Number is calculated by adding each individual number in that person's date of birth, until it is reduced to a single digit number.

Problem

We are required to write a JavaScript function that takes in a date in “yyyy-mm-dd” format and returns the life path number for that date of birth.

For instance,

if the date is: 1999-06-10

year : 1 + 9 + 9 + 9 = 28 → 2 + 8 = 10 → 1 + 0 = 1
month : 0 + 6 = 6
day : 1 + 0 = 1
result: 1 + 6 + 1 = 8

Example

Following is the code −

const date = '1999-06-10';
const findLifePath = (date = '') => {
   const sum = (arr = []) => {
      if(arr.length === 1){
         return +arr[0]
      };
      let total = arr.reduce((acc, val) => acc + val);
      if (total < 10){
         return total
      };
      return sum(String(total).split("").map(Number));
   };
   let [year, month, day] = date.split("-")
   year = sum(String(year).split("").map(Number));
   month = sum(String(month).split("").map(Number));
   day = sum(String(day).split("").map(Number));
   return sum([year,month,day]);
};
console.log(findLifePath(date));

Output

Following is the console output −