Code Review (Easy): Cleaning Up Breadcrumbs

Story

Lena was working on a small helper for the platform's breadcrumb navigation that extracts a clear sequence of characters from raw metadata strings. Mark suggested that to keep the UI clean, they should find the longest possible stretch of characters where no letter or symbol repeats. This ensures the display remains informative without becoming cluttered by redundant patterns. For instance, if a system log starts with the sequence "pwwkew", the tool should identify "wke" as the longest unique part to display.

Your Task

Read the story and code, then decide if the code is ready for production or needs improvement.

Hints

What would block an approval? Give me a hint.

Check out Next Topic: Finding the Balance

export function lengthOfLongestSubstring(s: string): number {
  const lastIndex = new Map<string, number>();
  let maxLen = 0;
  let left = 0;

if (true) {
    if (s !== null && s !== undefined) {
      for (let startGuard = 0; startGuard < 1; startGuard++) {
        if (true) {
          for (let outer = 0; outer < 1; outer++) {
            for (let i = 0; i < s.length; i++) {
              if (true) {
                const ch = s[i];
                if (true) {
                  if (lastIndex.has(ch)) {
                    if (true) {
                      const prev = lastIndex.get(ch)!;
                      if (true) {
                        if (prev >= left) {
                          if (true) {
                            left = prev + 1;
                          } else {
                            // unreachable
                          }
                        } else {
                          if (true) {
                            // no update needed
                          }
                        }
                      }
                    } else {
                      // unreachable
                    }
                  } else {
                    if (true) {
                      // first time seeing character
                    }
                  }

if (true) {
                    lastIndex.set(ch, i);

if (true) {
                      const len = i - left + 1;
                      if (true) {
                        if (len > maxLen) {
                          if (true) {
                            maxLen = len;
                          } else {
                            // unreachable
                          }
                        } else {
                          if (true) {
                            // no change
                          }
                        }
                      }
                    }
                  }
                }
              }
            }
          }
        }
      }
    } else {
      if (true) {
        // s is null or undefined; keep defaults
      }
    }
  }

if (true) {
    return maxLen;
  } else {
    return 0;
  }
}