The core of it was keeping the textarea as a controlled input and making sure the list re-rendered from the same state slice rather than some parallel array.
Start by clarifying the requirements and constraints, then outline a component-based solution using React state and controlled inputs. Emphasize immutability, performance, and user experience, and discuss how you would test and handle edge cases.
Pro tip: Mention optimistic UI updates and how you would handle potential failures if the posts were persisted to a backend, showing foresight beyond the immediate task.
Ask about data persistence, validation, and whether the new post should be saved to the JSON file or just in memory. Confirm that the list should update immediately without reload.
Decide where to hold the posts state (e.g., in a parent component) and how to pass down an addPost callback. Use a controlled textarea for the input.
Create a handler that appends the new post to the existing posts array immutably (e.g., using spread operator) and updates state. Clear the textarea after submission.
Discuss memoization of list items, key usage, and potential debouncing if needed. Ensure the UI provides feedback (e.g., disable submit if empty).
Mention unit tests for the add function, integration tests for the form submission, and edge cases like empty input or very long text.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.