v4.0.0

Breaking Changes

• react-dnd and react-dnd-html5-backend are now peer dependencies instead of
  bundled dependencies — install them alongside react-arborist (npm install react-arborist react-dnd react-dnd-html5-backend). This fixes a global singleton
  conflict (#319) where apps that also used react-dnd ended up with two independent
  copies of the library, causing drag-and-drop to silently break or throw "Cannot have
  two HTML5 backends at the same time." Both peers must be v16 (^16), and both are
  required even when you pass your own dndBackend / dndManager, because the drag
  preview calls into react-dnd-html5-backend on every drag. react-dnd v16 is ESM-only,
  and react-arborist now ships a single ESM build too (the CommonJS dist/main build is
  gone), so import and require load the same copy instead of two copies with
  separate React contexts. require("react-arborist") from CommonJS relies on
  require(esm), unflagged from Node 22.12 — now the engines.node floor, which
  package managers check at install time, so installing v4 requires Node ≥ 22.12 even
  for bundler and browser consumers. CommonJS TypeScript projects on Node module
  resolution need module: "nodenext" (TypeScript ≥ 5.8) or "node20" (TypeScript
  ≥ 5.9); "node16" and "node18" report TS1479. Jest users must add
  react-arborist to the transformIgnorePatterns exception list alongside react-dnd
  (see the README). The package also declares an exports map: react-arborist and
  react-arborist/package.json resolve as before, but deep imports such as
  react-arborist/dist/module/... are no longer resolvable. The react and react-dom
  peer floor rises from 16.14 to 18: the build now imports react/jsx-runtime
  and useSyncExternalStore directly from React, which older versions can't provide
  to ESM consumers. (#371)

Fixes

• @types/react-window is now a regular dependency instead of a dev dependency.
  react-arborist's public type declarations reference react-window types (onScroll,
  outerElementType, innerElementType, tree.list, scroll alignment), so without it
  TypeScript reported TS7016 under skipLibCheck: false and silently typed those as
  any otherwise. (#371)