How to break up string based on specific length after finding the whitespace nearest to the character limit?

Question

I have to break up a string field into multiple string fields if the original string exceeds a specific character limit. The original string can be of different lengths but the additional fields like string2, and string3 have a max character length of 10.

Question:

1. How can I break up a single string field into multiple string fields with defined character limits based on the nearest whitespace to the character limit?

Example:

1. Hello world, how are you doing?

Assumptions:

• originalString can be of different string lengths
• string1 is maxed at 15 characters
• string2 is maxed at 10 characters
• string3 is maxed at 10 characters
• first 15 characters for the originalString would be Hello world, ho
• next 10 characters would be w are you
• next 10 character would be doing?
• Do not break up whole words
• only populate street2 and street3 if required. if all characters can fit into street1 and street2 then street3 can be empty

What I tried that didn't work:

let originalString = `Hello world, how are you doing?`
if(originalString.length > 15) {
  let string1 = originalString.substring(0,15) // this returns `Hello World,`
  let string2 = ???? // stuck here - need help
  let string3 = ???? // stuck here - need help
}

Expected output:

• originalString = Hello world, how are you doing?
• string1 = Hello world,
• string2 = how are
• string3 = you doing?

Answer 1

The following will get you what you want:

• the first string containing up to 15 characters
• the second string containing up to 10 characters
• the third string containing up to 10 characters

The breaks will only be done before whitespace characters and never inside a word.

const originalString = `Hello world, how are you doing?`,
      res=originalString.match(/(.{1,15})\s+(.{1,10})\s+(.{1,10})(?:\s+.|$)/);
console.log(res.slice(1));