Mobile: Fix pasting in header (#14118)

* Fixes pasting in heading blocks.

* Fixed an issue with a missing constant.

* Removes some code that was added back as part of a merge conflict.

* Re-adds some code removed by mistake.

packages/block-library/src/heading/edit.native.js

@@ -16,7 +16,64 @@ import { Component } from '@wordpress/element';
 import { RichText, BlockControls } from '@wordpress/editor';
 import { createBlock } from '@wordpress/blocks';
 
+const name = 'core/heading';
+
+/**
+ * Internal dependencies
+ */
+import styles from './style.scss';
+
 class HeadingEdit extends Component {
+	constructor( props ) {
+		super( props );
+
+		this.splitBlock = this.splitBlock.bind( this );
+	}
+
+
+	/**
+	 * Split handler for RichText value, namely when content is pasted or the
+	 * user presses the Enter key.
+	 *
+	 * @param {?Array}     before Optional before value, to be used as content
+	 *                            in place of what exists currently for the
+	 *                            block. If undefined, the block is deleted.
+	 * @param {?Array}     after  Optional after value, to be appended in a new
+	 *                            paragraph block to the set of blocks passed
+	 *                            as spread.
+	 * @param {...WPBlock} blocks Optional blocks inserted between the before
+	 *                            and after value blocks.
+	 */
+	splitBlock( before, after, ...blocks ) {
+		const {
+			attributes,
+			insertBlocksAfter,
+			setAttributes,
+			onReplace,
+		} = this.props;
+
+		if ( after !== null ) {
+			// Append "After" content as a new paragraph block to the end of
+			// any other blocks being inserted after the current paragraph.
+			const newBlock = createBlock( name, { content: after } );
+			blocks.push( newBlock );
+		}
+
+		if ( blocks.length && insertBlocksAfter ) {
+			insertBlocksAfter( blocks );
+		}
+
+		const { content } = attributes;
+		if ( before === null ) {
+			onReplace( [] );
+		} else if ( content !== before ) {
+			// Only update content if it has in-fact changed. In case that user
+			// has created a new paragraph at end of an existing one, the value
+			// of before will be strictly equal to the current content.
+			setAttributes( { content: before } );
+		}
+	}
+
 	render() {
 		const {
 			attributes,
@@ -49,17 +106,7 @@ class HeadingEdit extends Component {
 					onCaretVerticalPositionChange={ this.props.onCaretVerticalPositionChange }
 					onChange={ ( value ) => setAttributes( { content: value } ) }
 					onMerge={ mergeBlocks }
-					onSplit={
-						insertBlocksAfter ?
-							( before, after, ...blocks ) => {
-								setAttributes( { content: before } );
-								insertBlocksAfter( [
-									...blocks,
-									createBlock( 'core/paragraph', { content: after } ),
-								] );
-							} :
-							undefined
-					}
+					onSplit={ this.splitBlock }
 					placeholder={ placeholder || __( 'Write heading…' ) }
 				/>
 			</View>

packages/editor/src/components/rich-text/index.native.js

@@ -97,9 +97,16 @@ export class RichText extends Component {
 	 */
 	getRecord() {
 		const { formatPlaceholder, start, end } = this.state;
+
+		var value = this.props.value === undefined ? null : this.props.value;
+
 		// Since we get the text selection from Aztec we need to be in sync with the HTML `value`
 		// Removing leading white spaces using `trim()` should make sure this is the case.
-		const { formats, text } = this.formatToValue( this.props.value === undefined ? undefined : this.props.value.trimLeft() );
+		if (typeof value === 'string' || value instanceof String) {
+			value = value.trimLeft();
+		}
+
+		const { formats, text } = this.formatToValue( value );
 
 		return { formats, formatPlaceholder, text, start, end };
 	}