AI solution for JavaScript Coding Question on BFE.dev
59. create a browser history

class BrowserHistory {
  constructor() {
    this.history = [];
    this.currentPos = -1;
  }
  
  visit(url) {
    // Truncate entries after current position
    this.history.splice(this.currentPos + 1);
    // Add new url to history
    this.history.push(url);
    // Update current position
    this.currentPos = this.history.length - 1;
  }
  
  goBack() {
    if (this.currentPos > 0) {
      this.currentPos--;
      return this.history[this.currentPos];
    }
    // If there are no previous entries, return current url
    return this.history[0];
  }
  
  forward() {
    if (this.currentPos < this.history.length - 1) {
      this.currentPos++;
      return this.history[this.currentPos];
    }
    // If there are no next entries, return current url
    return this.history[this.currentPos];
  }
  
}

We use an array to store the history and a current position pointer to keep track of the current entry. The visit() method adds a new url to the history, truncating entries after the current position. The goBack() and forward() methods move the current position and return the corresponding urls from the history. If there are no previous or next entries, the current url is returned.