[P2][开发者 API / Developer APIs] StrictMode、Effects、act 与 Profiler

中文

背景

核心应用能力已基本覆盖，但组件库作者和调试场景仍缺少部分稳定 API。它们的价值低于发布、文档、DOM 和事件可用性，因此列为 P2，并按独立价值逐项选择，而不是一次性追求数量完整。

候选范围与顺序

1. 公共 StrictMode helper
2. useInsertionEffect
3. 测试 API act
4. Profiler
5. useDebugValue

可量化验收

• 每个 API 在实现前关联 React 19.2 稳定契约并说明目标用户。
• StrictMode/Profiler 使用真实 Chromium lifecycle/callback 计数。
• Effect API 验证执行顺序、cleanup 次数与重新渲染行为。
• act 验证同步和异步更新在断言前完成。
• 每个 API 独立报告测试数与 diagnostics；非预期 diagnostics 为 0。

English

Background

Core application capabilities are largely covered, but component-library authors and debugging workflows still lack several stable APIs. Their value is lower than release delivery, documentation, DOM, and event usability, so this is a P2 objective and each API should be selected for independent value rather than API-count completeness.

Candidate scope and order

1. Public StrictMode helper
2. useInsertionEffect
3. Testing API act
4. Profiler
5. useDebugValue

Quantitative acceptance

• Before implementation, map each API to its stable React 19.2 contract and identify its target users.
• StrictMode and Profiler use real Chromium lifecycle or callback counts.
• Effect APIs verify ordering, cleanup counts, and rerender behavior.
• act verifies that synchronous and asynchronous updates settle before assertions.
• Report tests and diagnostics for every API independently; unexpected diagnostics are zero.

Start by selecting one candidate API from the listed order and map it to the React 19.2 stable contract and target users before implementation. Use the stated Chromium lifecycle or callback checks and API-specific effect, act, or diagnostics acceptance criteria to define completion; no files or tests are named in the issue.