wp_text_diff( string $left_string, string $right_string, string|array $args = null ): string

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

Description

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.

See also

Parameters

$left_stringstringrequired
"old" (left) version of string.
$right_stringstringrequired
"new" (right) version of string.
$argsstring|arrayoptional
Associative array of options to pass to WP_Text_Diff_Renderer_Table().
  • title string
    Titles the diff in a manner compatible with the output. Default empty.
  • title_left string
    Change the HTML to the left of the title.
    Default empty.
  • title_right string
    Change the HTML to the right of the title.
    Default empty.
  • show_split_view bool
    True for split view (two columns), false for un-split view (single column). Default true.

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'     => '',
		'show_split_view' => true,
	);
	$args     = wp_parse_args( $args, $defaults );

	if ( ! class_exists( 'WP_Text_Diff_Renderer_Table', false ) ) {
		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 '';
	}

	$is_split_view       = ! empty( $args['show_split_view'] );
	$is_split_view_class = $is_split_view ? ' is-split-view' : '';

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

	if ( $args['title'] ) {
		$r .= "<caption class='diff-title'>$args[title]</caption>\n";
	}

	if ( $args['title_left'] || $args['title_right'] ) {
		$r .= '<thead>';
	}

	if ( $args['title_left'] || $args['title_right'] ) {
		$th_or_td_left  = empty( $args['title_left'] ) ? 'td' : 'th';
		$th_or_td_right = empty( $args['title_right'] ) ? 'td' : 'th';

		$r .= "<tr class='diff-sub-title'>\n";
		$r .= "\t<$th_or_td_left>$args[title_left]</$th_or_td_left>\n";
		if ( $is_split_view ) {
			$r .= "\t<$th_or_td_right>$args[title_right]</$th_or_td_right>\n";
		}
		$r .= "</tr>\n";
	}

	if ( $args['title_left'] || $args['title_right'] ) {
		$r .= "</thead>\n";
	}

	$r .= "<tbody>\n$diff\n</tbody>\n";
	$r .= '</table>';

	return $r;
}

Changelog

VersionDescription
2.6.0Introduced.

User Contributed Notes

  1. Skip to note 2 content

    Example

    $left_string = 'This is the original string';
    
    $right_string = 'This is the revised string';
    
    $args = array(
    	'title'       => 'Differences',
    	'title_left'  => 'Old Version',
    	'title_right' => 'New Version'
    );
    
    $diff_table = wp_text_diff( $left_string,$right_string, $args );
    
    echo $diff_table;

    This will output the following html:

    [html]
    <table class="diff">
    <colgroup>
    <col class="ltype">
    <col class="content">
    <col class="ltype">
    <col class="content">
    </colgroup>
    <thead>
    <tr class="diff-title">
    <th colspan="4">Differences</th>
    </tr>
    <tr class="diff-sub-title">
    <td></td>
    <th>Old Version</th>
    <td></td>
    <th>New version</th>
    </tr>
    </thead>
    <tbody>
    <tr>
    <td>-</td>
    <td class="diff-deletedline">
    This is the <del>original</del> string
    </td>
    <td>+</td>
    <td class="diff-addedline">
    This is the <ins>revised</ins> string
    </td>
    </tr>

    </tbody>
    </table>
    [/html]

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