Class SinglyLinkedList<E, R>

Example

// implementation of a basic text editor
    class TextEditor {
      private content: SinglyLinkedList<string>;
      private cursorIndex: number;
      private undoStack: Stack<{ operation: string; data?: any }>;

      constructor() {
        this.content = new SinglyLinkedList<string>();
        this.cursorIndex = 0; // Cursor starts at the beginning
        this.undoStack = new Stack<{ operation: string; data?: any }>(); // Stack to keep track of operations for undo
      }

      insert(char: string) {
        this.content.addAt(this.cursorIndex, char);
        this.cursorIndex++;
        this.undoStack.push({ operation: 'insert', data: { index: this.cursorIndex - 1 } });
      }

      delete() {
        if (this.cursorIndex === 0) return; // Nothing to delete
        const deleted = this.content.deleteAt(this.cursorIndex - 1);
        this.cursorIndex--;
        this.undoStack.push({ operation: 'delete', data: { index: this.cursorIndex, char: deleted } });
      }

      moveCursor(index: number) {
        this.cursorIndex = Math.max(0, Math.min(index, this.content.length));
      }

      undo() {
        if (this.undoStack.size === 0) return; // No operations to undo
        const lastAction = this.undoStack.pop();

        if (lastAction!.operation === 'insert') {
          this.content.deleteAt(lastAction!.data.index);
          this.cursorIndex = lastAction!.data.index;
        } else if (lastAction!.operation === 'delete') {
          this.content.addAt(lastAction!.data.index, lastAction!.data.char);
          this.cursorIndex = lastAction!.data.index + 1;
        }
      }

      getText(): string {
        return [...this.content].join('');
      }
    }

    // Example Usage
    const editor = new TextEditor();
    editor.insert('H');
    editor.insert('e');
    editor.insert('l');
    editor.insert('l');
    editor.insert('o');
    console.log(editor.getText()); // 'Hello' // Output: "Hello"

    editor.delete();
    console.log(editor.getText()); // 'Hell' // Output: "Hell"

    editor.undo();
    console.log(editor.getText()); // 'Hello' // Output: "Hello"

    editor.moveCursor(1);
    editor.insert('a');
    console.log(editor.getText()); // 'Haello'
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