Displays a human readable HTML representation of the difference between two strings.

The Diff is available for getting the changes between versions. The output is HTML, so the primary use is for displaying the changes. If the two strings are equivalent, then an empty string will be returned.

The arguments supported and can be changed are listed below.

‘title’ : Default is an empty string. Titles the diff in a manner compatible with the output. ‘title_left’ : Default is an empty string. Change the HTML to the left of the title. ‘title_right’ : Default is an empty string. Change the HTML to the right of the title.

Signature

wp_text_diff( $left_string, $right_string, $args = null )
left_string
 (string) "old" (left) version of string
right_string
 (string) "new" (right) version of string
args
 (string|array) Optional. Change 'title', 'title_left', and 'title_right' defaults.
Default: null

Return

(string) Empty string if strings are equivalent or HTML with differences.

Source

function wp_text_diff( $left_string, $right_string, $args = null ) {
	$defaults = array( 'title' => '', 'title_left' => '', 'title_right' => '' );
	$args = wp_parse_args( $args, $defaults );

	if ( !class_exists( 'WP_Text_Diff_Renderer_Table' ) )
		require( ABSPATH . WPINC . '/wp-diff.php' );

	$left_string  = normalize_whitespace($left_string);
	$right_string = normalize_whitespace($right_string);

	$left_lines  = explode("\n", $left_string);
	$right_lines = explode("\n", $right_string);
	$text_diff = new Text_Diff($left_lines, $right_lines);
	$renderer  = new WP_Text_Diff_Renderer_Table( $args );
	$diff = $renderer->render($text_diff);

	if ( !$diff )
		return '';

	$r  = "<table class='diff'>\n";
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