Add disableSelect prop (rebased from #169)

[TrevorBurnham]

Resurrects @boriskor's #169, rebased onto current main with style cleanup. Closes #56.

Summary

Adds a disableSelect Tree prop in the spirit of disableEdit and disableDrag — accepts string | boolean | BoolFunc<T>. When the predicate returns true for a node, that node can't be selected via click, keyboard, selectionFollowsFocus, selectAll, or any of the imperative select methods. Focus still moves through the disabled node (so keyboard navigation isn't blocked); only selection is gated.

Closes #56, which @jameskerr opened in 2022 asking for exactly this API.

What changed vs #169

• Rebased onto current main (resolved conflicts with Add options argument to selectMulti for consistency with select #266's selectMulti(opts) and the isActionPossible refactor).
• Style cleanup commit on top: matched repo formatting in filterSelectableNodes / selectContiguous, replaced an as NodeApi<T>[] cast with a type-guarded filter predicate.
• Original commits preserved with @boriskor as author.

Coverage

• Gates select, selectMulti, selectContiguous, selectAll. selectionFollowsFocus flows through select so it's gated too.
• setSelection (imperative escape hatch) is intentionally not gated.
• Adds node.isSelectable getter on NodeApi.
• Cypress e2e tests against the Gmail showcase (covers click + select-all behaviors).
• Showcase updated to demo with Categories/Spam disabled.
• README documents the new prop.

Test plan

• CI green (build + existing tests)
• e2e: clicking Categories doesn't select it; cmd-A skips Categories and Spam
• Manual: arrow-key navigation still passes through a disabled node when selectionFollowsFocus is on, but the node doesn't get selected
• Manual: existing selection is preserved when clicking a disabled node (not cleared)

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds a disableSelect prop to Tree (matching the existing disableEdit / disableDrag patterns) to prevent certain nodes from being selectable while still allowing focus/navigation through them.

Changes:

• Introduces disableSelect?: string | boolean | BoolFunc<T> to TreeProps and documents it in the README.
• Gates selection entry points (select, selectMulti, selectContiguous, selectAll) based on a new node.isSelectable getter.
• Updates the Gmail showcase + Cypress e2e coverage to demonstrate and validate unselectable nodes.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
modules/showcase/pages/gmail.tsx	Demonstrates disableSelect by preventing selection of “Categories” and “Spam”.
modules/react-arborist/src/types/tree-props.ts	Adds disableSelect to the public TreeProps type.
modules/react-arborist/src/interfaces/tree-api.ts	Implements select-gating and introduces isSelectable() / filterSelectableNodes().
modules/react-arborist/src/interfaces/node-api.ts	Adds node.isSelectable getter.
modules/e2e/cypress/e2e/gmail-spec.cy.js	Adds e2e tests for click selection + select-all behavior with unselectable nodes.
README.md	Documents the new disableSelect prop in the TreeProps interface section.
CONTRIBUTING.md	Tweaks local testing instructions formatting.

Comments suppressed due to low confidence (1)

modules/react-arborist/src/interfaces/tree-api.ts:342

• select() now calls setSelection() (which already invokes props.onSelect) and then invokes props.onSelect again at the end of select(). This results in duplicate onSelect callbacks for a single selection change, which can cause double side-effects for consumers. Consider either removing the onSelect call inside setSelection, or making select() use dispatches directly / return early so onSelect is only fired once per action.

    if (this.get(id)?.isSelectable) {
      this.setSelection({
        ids: [id],
        anchor: id,
        mostRecent: id,
      });
    }
    this.scrollTo(id, opts.align);
    if (this.focusedNode && changeFocus) {
      safeRun(this.props.onFocus, this.focusedNode);
    }
    safeRun(this.props.onSelect, this.selectedNodes);

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[TrevorBurnham]

Pushed fd9ab93 addressing Copilot's review:

• select() double onSelect (suppressed comment) — dropped the trailing safeRun(onSelect, ...) since setSelection already fires it. Was a regression introduced by this PR.
• selectAll() anchor/mostRecent (Tree.onSelect #1) — derived from the selectable subset (null when none are selectable) so subsequent shift-click ranges don't start from a non-selected node.
• e2e Inbox-survives-Categories-click (If a meta key is held, don't toggle the group. #2) — added the assertion that existing selection is preserved after clicking an unselectable node.
• CONTRIBUTING.md autolink (TreeApi.selectById(id) #3) — added http:// scheme so it renders as a link.

Not addressed (left as a follow-up to keep this PR scoped):

• selectAll() / deselectAll() double onSelect (TreeApi.edit should scroll you to that item as well. #4) — pre-existing on main, not introduced by this PR. Will open a separate cleanup ticket since the same pattern likely deserves a sweep across all the selection methods.

[TrevorBurnham]

Follow-up cleanup tracked in #332.