Deal with components that don't have children

truncate the html content before stripping it. cuts down on the amount of memory needed to run this check with large contents.

add in support for neutral characters in the text

call the isRTL function. Helps that.

client/components/auto-direction/index.jsx

@@ -11,14 +11,24 @@ import { stripHTML } from 'lib/formatting';
 
 const user = userModule();
 
+const RTL_THRESHOLD = 0.5;
+const MAX_LENGTH_OF_TEXT_TO_EXAMINE = 100;
+
 /***
  * Gets text content from react element in case that's a leaf element
  * @param {React.Element} reactElement react element
  * @returns {string|null} returns a text content of the react element or null if it's not a leaf element
  */
 const getContent = ( reactElement ) => {
+	if ( ! reactElement ) {
+		return null;
+	}
 	const { props } = reactElement;
 
+	if ( ! props ) {
+		return null;
+	}
+
 	// The child is a text node
 	if ( typeof props.children === 'string' ) {
 		return props.children;
@@ -28,7 +38,7 @@ const getContent = ( reactElement ) => {
 	if ( typeof props.dangerouslySetInnerHTML === 'object' ) {
 		// Strip tags because we're only interested in the text, not markup
 		return props.dangerouslySetInnerHTML.__html
-			? stripHTML( props.dangerouslySetInnerHTML.__html )
+			? stripHTML( props.dangerouslySetInnerHTML.__html.substring( 0, Math.floor( MAX_LENGTH_OF_TEXT_TO_EXAMINE * 1.25 ) ) )
 			: '';
 	}
 
@@ -100,14 +110,18 @@ const rtlCharacterRanges = [
 	},
 ];
 
-const RTL_THRESHOLD = 0.5;
-const MAX_LENGTH_OF_TEXT_TO_EXAMINE = 100;
+
 
 const isRTLCharacter = ( character ) => {
 	const characterCode = character.charCodeAt( 0 );
 	return rtlCharacterRanges.some( range => range.start <= characterCode && range.end >= characterCode );
 };
 
+const whitespaceRe = /[\s\-\_0-9]/u;
+const isNeutralCharacter = ( character ) => {
+	return whitespaceRe.test( character );
+}
+
 /***
  * Gets the main directionality in a text
  * It returns what kind of characters we had the most, RTL or LTR according to some ratio
@@ -117,12 +131,21 @@ const isRTLCharacter = ( character ) => {
  */
 const getTextMainDirection = ( text ) => {
 	let rtlCount = 0;
+	let countedCharacters = 0;
 	const examinedLength = Math.min( MAX_LENGTH_OF_TEXT_TO_EXAMINE, text.length );
 	for ( let i = 0; i < examinedLength; i++ ) {
+		if ( isNeutralCharacter( text[ i ] ) ) {
+			continue;
+		}
 		rtlCount += isRTLCharacter( text[ i ] ) ? 1 : 0;
+		countedCharacters++;
 	}
 
-	return ( rtlCount / examinedLength > RTL_THRESHOLD ) ? 'rtl' : 'ltr';
+	if ( countedCharacters === 0 ) {
+		return user.isRTL() ? 'rtl' : 'ltr';
+	}
+
+	return ( rtlCount / countedCharacters > RTL_THRESHOLD ) ? 'rtl' : 'ltr';
 };
 
 /***
@@ -154,9 +177,13 @@ const setChildDirection = ( child ) => {
 		return child;
 	}
 
-	return React.cloneElement( child, {
-		children: React.Children.map( child.props.children, setChildDirection )
-	} );
+	if ( child && child.props.children ) {
+		return React.cloneElement( child, {
+			children: React.Children.map( child.props.children, setChildDirection )
+		} );
+	}
+
+	return child;
 };
 
 /***