React Wrapper Development

Package location

wrappers/react-wrapper/

Components

• HotTable - the public component users import. Renders a container div and bootstraps Handsontable.
• HotTableInner - a forwardRef wrapper that handles the actual instance lifecycle.
• HotColumn - declarative column configuration as a child of HotTable.
• HotEditor - renders a custom editor component inside a React portal.

Architecture

A useRef() hook holds the live Handsontable instance. It is exposed to parent components through useImperativeHandle(), so consumers can call hotInstance.current to access the grid API directly.

SettingsMapper.getSettings() converts React props into a plain Handsontable settings object. Every prop change triggers updateSettings() on the instance.

Critical rule: When calling updateSettings(), you must preserve and restore the current selection. Before the call, snapshot the selection with selection.exportSelection(). After the call, restore it with selection.importSelection(). Forgetting this causes the selection to reset on every prop change.

Custom hooks and portals

• useHotEditor() - a hook for building component-based cell editors. It gives the editor component access to the editor lifecycle (open, close, getValue, setValue).
• React portals are used to render React components inside Handsontable cells (for renderers and editors). A React context propagates the Handsontable instance to these portals.

Build and test

• Build system: Rollup 4 producing CommonJS, ES module, UMD, and minified outputs.
• Tests: Jest with React Testing Library.
• Run tests: npm run test --prefix wrappers/react-wrapper
• Important: Build core first with npm run build --prefix handsontable. Wrappers consume handsontable/tmp/, not dist/.

Key files

File	Purpose
src/hotTable.tsx	Public HotTable component
src/hotTableInner.tsx	Inner component with instance lifecycle
src/settingsMapper.ts	Converts React props to Handsontable settings
src/hotColumn.tsx	Declarative column config component
src/hotEditor.tsx	Custom editor portal component

TypeScript prop types and the declaration build (read before touching src/types.tsx)

The published .d.ts files are generated by scripts/prepare-types.mjs, which runs this package's own typescript devDep — currently 3.8.2 (2020) — and deliberately swallows tsc errors, so a mangled declaration still reports "prepared successfully."

• Define modern type helpers in the core package and import them here. TS 3.8 cannot emit 4.1+ syntax such as key-remapping ({ [K in keyof T as ...]: ... }); it silently produces garbage like { [K in keyof T]: ; }. Keep such helpers in handsontable/src (built with modern TS) and import them, e.g. RemoveIndexSignature lives in handsontable/src/settings.ts and reaches the wrapper via handsontable/base.
• After changing any type in src/, verify the emitted declaration. Pack the core and wrapper (npm pack), install both into a throwaway project, and tsc --noEmit a file that uses the props — this is the reliable signal, since the build itself hides declaration errors.
• Strip the index signature before Omit/Pick on a settings type. GridSettings/ColumnSettings carry a [key: string]: any escape hatch for plugin/meta keys. Wrap the input in RemoveIndexSignature<T> first (as ReplaceRenderersEditors does) so the named options survive Omit — without it keyof widens to string, every option name is dropped, and IDE autocomplete inside <HotTable>/<HotColumn> breaks. Build column props from RemoveIndexSignature<GridSettings> and override data with ColumnSettings['data'] — do this in the wrapper rather than making core ColumnSettings strict, because tightening a shipped core type breaks existing loose column configs (columns: [{ validator: (v: string) => … }]) across every framework. (Interface extends keeps the options but can't override renderer/editor/data, whose types differ.) Finally, re-add & { [key: string]: any } to the prop type so undeclared cell-type/plugin options (correctFormat, datePickerConfig, …) stay assignable; named options keep their real types regardless, exactly like React.CSSProperties. A prop type without this hatch fails on real configs (e.g. a date column passing correctFormat).
• Lint through the monorepo-level lint command. This package has no lint script or local .eslintrc, so run the root lint (which supplies the TS/JSX-aware parser) rather than a per-file invocation.

React StrictMode gotcha

React StrictMode causes a double mount (mount -> unmount -> mount). This means Handsontable gets initialized twice. The wrapper must correctly destroy the instance on unmount and create a fresh one on the second mount. If cleanup is incomplete, the second mount can fail or leak memory. Always verify that destroy() is called on unmount and that no stale references persist.

Rules

• No business logic in wrappers. Data transformation, validation, and grid behavior belong in handsontable/src/.
• Cross-platform npm scripts: use Node.js .mjs helpers instead of bash-only constructs (see scripts/prepare-types.mjs as reference).