Counting words in string

I was trying to count words in a text in this way:

function WordCount(str) {
  var totalSoFar = 0;
  for (var i = 0; i < WordCount.length; i++)
    if (str(i) === " ") { // if a space is found in str
      totalSoFar = +1; // add 1 to total so far
  }
  totalsoFar += 1; // add 1 to totalsoFar to account for extra space since 1 space = 2 words
}

console.log(WordCount("Random String"));

I think I have got this down pretty well, except I think that the if statement is wrong. The part that checks if str(i) contains a space and adds 1.

Edit:

I found out (thanks to Blender) that I can do this with a lot less code:

function WordCount(str) { 
  return str.split(" ").length;
}

console.log(WordCount("hello world"));

Answer

Use square brackets, not parentheses:

str[i] === " "

Or charAt:

str.charAt(i) === " "

You could also do it with .split():

return str.split(' ').length;