Can you please explain what is happening in that function?

Question

JavaScript

Good afternoon

There is a code that capitalizes every first letter in a phrase

here is the code

const word = (str) => {
  let result = '';
  for (let i = 0; i < length(str); i += 1) {
    console.log(str[i]); 
    
    const world = str[i] !== ' ' && (i === 0 || str[i - 1] === ' ');
    result += world ? toUpperCase(str[i]) : str[i];
    
  }

return result;
};

document.write(word('просто рандомная фраза'));

Everything works fine, but it is not clear what is happening in these lines:

const world = str[i] !== ' ' && (i === 0 || str[i - 1] === ' ');
result += world ? toUpperCase(str[i]) : str[i];

Please explain more specifically, I want to understand ...

P / s: This code is taken from the lesson, and it works there, but not in the sandbox, for the sandbox, I rewrote it a little, but it didn’t become clearer

const word = (str) => {
  let result = '';
  for (let i = 0; i < str.length; i += 1) {
    console.log(str[i]); 
    
    const current = str[i] !== ' ' && (i === 0 || str[i - 1] === ' ');
 
    result += current ? str[i].toUpperCase() : str[i];
    
  }

return result;
};

document.write(word('просто рандомная фраза'));

Answer 1

// это условие, при котором букву надо делать большой
const world = str[i] !== ' ' && (i === 0 || str[i - 1] === ' ');

// здесь добавляется либо заглавная, либо просто-как-есть буква,
// в зависимости от условия выше
result += world ? toUpperCase(str[i]) : str[i];

The condition is parsed like this: the
current letter is not a space str[i] !== ' '
AND it is the first letter in the string i === 0OR the previous character is a space str[i - 1] === ' '
The bad thing here is that non-first letters are not handled in any way. From the string "habraHabr" you get "HabraHabr", although it would probably be more correct "Habrahabr"