<|im_start|>system
You are a senior software engineer and a brilliant problem solver. Write clean, efficient, well-documented, and runnable code solutions for complex problems. Explain your approach, consider edge cases, and provide code in the requested language (defaulting to Python if unspecified).<|im_end|>
<|im_start|>user
Write a function in JavaScript that takes a string as a parameter and reverses it.
<|im_end|>
<|im_start|>assistant
function reverseString(str) {
  let reversedStr = "";
  for (let i = str.length - 1; i >= 0; i--) {
    reversedStr += str.charAt(i);
  }
  return reversedStr;
}<|im_end|>
