JavaScript: regex CamelCase to Sentence

Question

I've found this example to change CamelCase to Dashes. I've modified to code to change CamelCase to Sentencecase with spaces instead of dashes. It works fine but not for one word letters, like "i" and "a". Any ideas how to incorporate that as well?

• thisIsAPain --> This is a pain

  var str = "thisIsAPain"; 
  str = camelCaseToSpacedSentenceCase(str);
  alert(str)
  
  function camelCaseToSpacedSentenceCase(str)
  {
      var spacedCamel = str.replace(/\W+/g, " ").replace(/([a-z\d])([A-Z])/g, "$1 $2");
      spacedCamel = spacedCamel.toLowerCase();
      spacedCamel = spacedCamel.substring(0,1).toUpperCase() + spacedCamel.substring(1,spacedCamel.length)
      return spacedCamel;
  }
  

Answer 1

The very last version:

"thisIsNotAPain"
    .replace(/^[a-z]|[A-Z]/g, function(v, i) {
        return i === 0 ? v.toUpperCase() : " " + v.toLowerCase();
    });  // "This is not a pain"

The old solution:

"thisIsAPain"
    .match(/^(?:[^A-Z]+)|[A-Z](?:[^A-Z]*)+/g)
    .join(" ")
    .toLowerCase()
    .replace(/^[a-z]/, function(v) {
        return v.toUpperCase();
    });  // "This is a pain"

console.log(
    "thisIsNotAPain"
        .replace(/^[a-z]|[A-Z]/g, function(v, i) {
            return i === 0 ? v.toUpperCase() : " " + v.toLowerCase();
        })  // "This is not a pain" 
);

console.log(
    "thisIsAPain"
        .match(/^(?:[^A-Z]+)|[A-Z](?:[^A-Z]*)+/g)
        .join(" ")
        .toLowerCase()
        .replace(/^[a-z]/, function(v) {
            return v.toUpperCase();
        })  // "This is a pain"
);

Answer 2

Change the first line of your function to

var spacedCamel = str.replace(/([A-Z])/g, " $1");

Answer 3

The algorithm to this is as follows:

1. Add space character to all uppercase characters.
2. Trim all trailing and leading spaces.
3. Uppercase the first character.

Javascript code:

function camelToSpace(str) {
    //Add space on all uppercase letters
    var result = str.replace(/([A-Z])/g, ' $1').toLowerCase();
    //Trim leading and trailing spaces
    result = result.trim();
    //Uppercase first letter
    return result.charAt(0).toUpperCase() + result.slice(1);
}

Refer to this link