[lexical-playground] Bug Fix: importing an unparseable data-lexical-datetime no longer breaks serialization

[LeSingh1]

Description

DateTimeRule builds a node from the attribute without checking that it parsed:

const DateTimeRule = defineImportRule({
  $import: (ctx, el) => {
    const dateTimeValue = el.getAttribute('data-lexical-datetime')!;
    const node = $createDateTimeNode(new Date(Date.parse(dateTimeValue)));   // NaN -> Invalid Date
    const [firstChild] = ctx.$importChildren(el);
    ...
    return [node];
  },
  match: sel.tag('span').attr('data-lexical-datetime', true),

GoogleDocsDateRule, twenty lines below in the same file and matching the same kind of pasted markup, does exactly the check that is missing:

if (isNaN(parsedDate)) {
  return $next();
}

When Date.parse fails, the rule still claims the element and returns the node, so $next() is never reached and the element's own text is discarded. The node then holds an Invalid Date, and its state config unparses with toISOString():

const dateTimeState = createState('dateTime', {
  parse: v => new Date(v as string),
  unparse: v => v.toISOString(),
});

Date.prototype.toISOString throws RangeError: Invalid time value on an Invalid Date, and LexicalNodeState.toJSON calls unparse for any value that differs from the default — which an Invalid Date object always does.

Measured on upstream/main, pasting <span data-lexical-datetime="not a date">some text</span>:

INVALID       text= "Invalid Date NaN:NaN"   toJSON THREW: RangeError Invalid time value
GDOCS-INVALID text= "gd text"                toJSON: OK
VALID         text= "Thu May 28 2026 17:00"  toJSON: OK

So one bad attribute in pasted HTML both replaces the visible text with Invalid Date NaN:NaN and makes the whole editor state unserializable: every later editorState.toJSON() throws, which is what the playground's autosave, the shareable-document URL, collab and the debug tree view all call. The document cannot be saved again until that node is deleted. The sibling rule shows the intended handling — fall through and keep the element as ordinary content.

This adds the same guard. $next was already part of the rule signature, it simply was not used here. No API or serialization change.

Test plan

New unit test packages/lexical-playground/__tests__/unit/DateTimeImport.test.ts. Two of the three cases are controls that pass before and after: a parseable date must still import, and the Google Docs rule's existing behaviour is asserted alongside so the two rules are pinned to the same contract.

Before

 ❯ packages/lexical-playground/__tests__/unit/DateTimeImport.test.ts (3 tests | 1 failed)
   × keeps the element content when the date cannot be parsed
     AssertionError: expected true to be false // Object.is equality
   ✓ still imports a parseable date
   ✓ matches how the Google Docs rule already handles an unparseable date

 Test Files  1 failed (1)
      Tests  1 failed | 2 passed (3)

After

 Test Files  1 passed (1)
      Tests  3 passed (3)

Package suite is unchanged:

$ npx vitest run packages/lexical-playground
 Test Files  19 passed (19)
      Tests  277 passed (277)

[vercel]

@LeSingh1 is attempting to deploy a commit to the Meta Open Source Team on Vercel.

A member of the Team first needs to authorize it.

[mayrang]

Ran the new test on main (1 failure as expected) and on this branch (3/3 pass). The isNaN guard mirrors GoogleDocsDateRule exactly. Three minor notes inline on the test file.

[mayrang]

The annotation and type import are redundant — buildEditorFromExtensions returns LexicalEditorWithDispose which already satisfies Disposable. The rest of the playground tests (e.g. CardNode.test.ts) use bare using editor = buildEditorFromExtensions(...).

[mayrang]

The /* @__PURE__ */ annotation on a test-only constant has no effect (tests aren't tree-shaken). The nearby playground tests drop it for defineExtension calls — this one stands out.

[mayrang]

The other two cases assert result.text; this one doesn't. A regression that creates an empty DateTimeNode (dropping "May 29") would still pass. Consider adding expect(result.text).toBe('May 29').