When validating SWC transform snapshot changes, update the Rust fixtures with UPDATE=1 cargo test -p swc_plugin_snapshot and UPDATE=1 cargo test -p swc_plugin_list --features napi so the stored snapshots match the current transform output. When a crate exposes both core Rust structs and napi wrapper structs with the same semantic shape, keep internal transform pipelines and shared Rc<RefCell<...>> state on the core types and convert to the napi types only at the JS boundary. Do not mix swc_plugin_*::napi::* record types into internal plugin wiring such as .with_*_records(...), or wasm builds can fail with mismatched type errors. When recording source locations from SWC spans, guard SourceMap::lookup_char_pos for synthetic spans such as DUMMY_SP (span.lo == 0). Compat and other transforms may synthesize JSX nodes with default spans, and wasm builds can surface panics from source map lookups on those spans as RuntimeError: unreachable. Expose recorded columns as 1-based values so uiSourceMapRecords can be fed directly into editor locations such as VS Code without an extra offset conversion. When compat wraps a component with a synthetic <view>, preserve the original component spans on the generated wrapper instead of using DUMMY_SP or Default::default(). Snapshot ui source map extraction reads opening.span, so preserved spans keep uiSourceMapRecords file, line, and column data intact. Keep snapshot.filename stable for snapshot hashing semantics, even when callers want absolute paths in exported debug metadata. If uiSourceMapRecords.filename needs to use the top-level transform filename, inject it at the react/transform/src/lib.rs boundary instead of changing the snapshot plugin's internal filename. If swc_plugin_snapshot::JSXTransformer::new gains a new constructor parameter, update every external callsite under packages/react/transform/** at the same time, including wrapper crates such as swc-plugin-reactlynx, not just the main packages/react/transform/src/lib.rs entrypoint. In swc_plugin_snapshot::DynamicPartExtractor, native JSX elements manually inspect and extract opening attributes before recursing into children. After that point, recurse with n.children.visit_mut_with(...) instead of n.visit_mut_children_with(...); the latter also revisits opening attrs and can incorrectly extract JSX inside prop expressions, such as children={items.map(...)}, into parent snapshot slots outside the expression's lexical scope. In swc_plugin_compat, do not use short-circuit scans like iter().any() when JSXSpread and explicit removeComponentElement can appear together on the same component. Collect the full opening-attr state first so removeComponentElement={true} compiles consistently regardless of whether it appears before or after {...props}, and only emit the compilerOnly JSXSpread warning when no explicit removeComponentElement={true} already disables wrapping.