wp_text_diff() – Function | Developer.WordPress.org

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.

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;
}

View all references View on Trac View on GitHub

Uses	Description
normalize_whitespace()`wp-includes/formatting.php`	Normalizes EOL characters and strips duplicate whitespace.
WP_Text_Diff_Renderer_Table::__construct()`wp-includes/class-wp-text-diff-renderer-table.php`	Constructor – Call parent constructor with params array.
wp_parse_args()`wp-includes/functions.php`	Merges user defined arguments into defaults array.

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Used by	Description
wp_get_revision_ui_diff()`wp-admin/includes/revision.php`	Get the revision UI diff.

Changelog

Version	Description
2.6.0	Introduced.

User Contributed Notes

Skip to note 2 content

Codex 10 years ago

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

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