WordPress \ Formatting : Prepends a leading slash and removes leading forward slashes and backslashes if they exist.

wp-leadingslash.php

<?php

/**
 * Prepends a leading slash.
 *
 * Will remove leading forward and backslashes if it exists already before adding
 * a leading forward slash. This prevents double slashing a string or path.
 *
 * The primary use of this is for paths and thus should be used for paths. It is
 * not restricted to paths and offers no specific path support.
 *
 * Opposite of {@see WordPress\trailingslashit()}.
 *
 * @param string $string What to add the leading slash to.
 * @return string String with leading slash added.
 */

function leadingslashit( $string )
{
	return '/' . unleadingslashit( $string );
}

/**
 * Removes leading forward slashes and backslashes if they exist.
 *
 * The primary use of this is for paths and thus should be used for paths. It is
 * not restricted to paths and offers no specific path support.
 *
 * Opposite of {@see WordPress\untrailingslashit()}.
 *
 * @param string $string What to remove the leading slashes from.
 * @return string String without the leading slashes.
 */

function unleadingslashit( $string )
{
	return ltrim( $string, '/\\' );
}