Sentences capitalization in JavaScript

sentences_capitalization.js

//spec
capitalize('my mom is cooking') // My Mom Is Cooking
capitalize('wait, I'm coming!') // Wait I'm Coming!

//solution 1
function capitalize(str) {
  const words = [];
  
  for(let word of str.split(' ')){
    words.push(word[0].toUpperCase() + word.slice(1))
  }
  
  return words.join(' ');
}

//solution 2
function capitalize(str) {
  let result = str[0].toUpperCase();
  for(let i = 1; i<str.length; i++) {
    if(str[i - 1] === ' '){
      result += str[i].toUpperCase();
    }else{
      result += str[i];
    }
  }
  
  return result;
}