---
id: 6997
title: Implement Effect Memoization
state: OPEN
labels:
  - enhancement
  - help wanted
  - good first issue
  - no auto close
  - hacktoberfest
assignees: []
createdAt: '2025-07-09T10:57:37Z'
updatedAt: '2025-10-08T09:42:48Z'
githubUrl: 'https://github.com/neomjs/neo/issues/6997'
author: tobiu
commentsCount: 1
parentIssue: 6992
subIssues: []
subIssuesCompleted: 0
subIssuesTotal: 0
blockedBy: []
blocking: []
---
# Implement Effect Memoization

### 1. Summary

Enhance the `Neo.core.Effect` system (or provide a utility around it) to support memoization for VDOM-generating methods. This will significantly improve rendering performance by caching the VDOM output and preventing unnecessary re-executions when component configs (inputs) have not changed.

### 2. Rationale

Functional components, driven by `Neo.core.Effect`, re-generate their VDOM whenever a tracked config changes. While efficient, re-generating complex VDOM trees can still be computationally intensive. By memoizing the output of pure VDOM-generating methods, we can avoid redundant work. If the inputs to `createVdom()` are the same as the last execution, the cached VDOM can be returned directly, bypassing the VDOM generation and worker communication steps.

### 3. Scope & Implementation Plan

1.  **Memoization Mechanism:** Design and implement a caching layer for `Neo.core.Effect` instances (or a new `MemoizedEffect` class). This mechanism will:
    *   Store the last computed VDOM output.
    *   Efficiently compare current inputs (tracked configs) with previous inputs to determine if re-execution is necessary.
    *   Invalidate the cache when inputs change.
2.  **Integration:** Determine how developers will opt-in to memoization (e.g., a config on `FunctionalBase`, a decorator, or a utility function).
3.  **Performance Testing:** Create benchmarks to measure the performance gains achieved through memoization, especially for components with complex VDOM structures or frequently updated but unchanged inputs.

### 4. Definition of Done

-   A memoization mechanism for `Neo.core.Effect` is implemented.
-   Functional components can leverage memoization to improve rendering performance.
-   Performance benchmarks demonstrate measurable gains.

## Timeline

- 2025-07-09T10:57:38Z @tobiu added parent issue #6992
- 2025-07-09T10:57:39Z @tobiu added the `enhancement` label
### @github-actions - 2025-10-08T02:38:37Z

This issue is stale because it has been open for 90 days with no activity.

- 2025-10-08T02:38:38Z @github-actions added the `stale` label
- 2025-10-08T09:42:47Z @tobiu removed the `stale` label
- 2025-10-08T09:42:47Z @tobiu added the `help wanted` label
- 2025-10-08T09:42:48Z @tobiu added the `good first issue` label
- 2025-10-08T09:42:48Z @tobiu added the `no auto close` label
- 2025-10-08T09:42:48Z @tobiu added the `hacktoberfest` label

