Fix pasting content with newlines on Android

[jason0x43]

Description

This is another potential solution for #5190 (see also #5195).

The root issue is with how text with newlines is handled on Android. If an InputEvent's data is a simple string containing newlines, the event handler inserts a soft break and then drops the rest of the event data.

slate/packages/slate-react/src/hooks/android-input-manager/android-input-manager.ts

Lines 586 to 590 in 1d8010b

	if (typeof data === 'string' && data.includes('\n')) {
	return scheduleAction(() => Editor.insertSoftBreak(editor), {
	at: Range.end(targetRange),
	})
	}

This PR updates the InputEvent handling code on Android so that when newlines are involved, the insertion is broken into single-line text insertions with soft breaks between them. It also makes some minor type improvements around the affected code.

Issue

Fixes: #5190

Example

Current behavior	New behavior

Context

#5195 fixed this issue by scheduling an insertText for text containing newlines rather than updating the diff. This PR is similar, but it replaces any newlines with soft breaks. It also strips the trailing newline that Android appends to clipboard text that contains newlines. This approach seemed reasonable given its simplicity, and given that inserts involving newlines are much less common than inserts without newlines.

This fix has been tested on a Pixel 4 running Android 12 and a couple of Samsung Galaxies running Android 12 and 13, with Gboard, Swiftkey, and Samsung keyboard. Copying and then pasting text within a paragraph, after a paragraph, and pasting over a text selection all appear to work as expected, whether the copied text contains newlines or not.

In a comment, @BitPhinix suggested there might be issues with this general approach with certain IMEs when inserting newlines in paragraphs, but I've been unable reproduce this behavior. The keyboards I've tested generate insertParagraph events (Gboard, Swiftkey, Samsung) when pressing enter at the beginning of a word or within a word, or insertCompositionText events (Gboard, Swiftkey) when the return key is pressed (the Samsung keyboard still generates an insertParagraph for this case). An example that behaves differently would be very useful for testing.

Checks

• The new code matches the existing patterns and styles.
• The tests pass with yarn test.
• The linter passes with yarn lint. (Fix errors with yarn fix.)
• The relevant examples still work. (Run examples with yarn start.)
• You've added a changeset if changing functionality. (Add one with yarn changeset add.)

[changeset-bot]

🦋 Changeset detected

Latest commit: a5ef299

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
slate-react	Patch

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[dylans]

This looks fine, needs a changeset (set change level as patch) and then we can land it.

[jason0x43]

Changeset added