PHP port of classnames.js

classnames.php

<?php

/**
 * PHP port of https://github.com/JedWatson/classnames
 *
 * Examples:
 * <code>
 * classnames('foo', 'bar'); // "foo bar"
 * classnames('foo', ['bar' => true]); // "foo bar"
 * classnames(['foo-bar' => true]); // "foo-bar"
 * classnames(['foo-bar' => false]); // ""
 * classnames(['foo' => true], ['bar' => true]); // "foo bar"
 * classnames(['foo' => true, 'bar' => true]); // "foo bar"
 * classnames(' ', ['  foo  ', ''], ['' => true]); // "foo" (empty strings and whitespace ignored)
 * classnames('foo bar', ['foo' => true], ['bar', 'foo']); // "foo bar" (duplicates removed)
 * classnames('foo', ['foo' => false], ['foo' => true]); // "" (false trumps all others)
 * </code>
 *
 * @param array|string $names
 *
 * @return string
 */
function classnames($names) {
    static $recursion = false, $falsified;
    if (!$recursion) {
        $falsified = array();
    }
    $classes = array();
    foreach (func_get_args() as $arg) {
        if (!$arg) { continue; }
        if (is_scalar($arg)) {
            $classes[] = trim((string) $arg);
        } elseif (is_assoc($arg)) {
            /** @var array $arg */
            foreach ($arg as $key => $result) {
                if ($result) {
                    $classes[] = trim($key);
                } else {
                    foreach (array_filter(explode(' ', $key)) as $k) {
                        $falsified[] = $k;
                    }
                }
            }
        } elseif (is_array($arg)) {
            $recursion = true;
            $classes[] = classnames($arg);
            $recursion = false;
        } elseif (is_object($arg) && method_exists($arg, '__toString')) {
            $classes[] = $arg->__toString();
        }
    }

    if (empty($classes)) { return ''; }

    $classes = array_unique(explode(' ', implode(' ', $classes)));
    $classes = array_diff($classes, $falsified);

    return implode(' ', array_filter($classes));
}

html_attributes.php

<?php

/**
 * Like "classnames()" above, but for HTML attributes.
 *
 * @param array|array[] $arguments
 *
 * @return string
 */
function html_attributes($arguments) {
    $html = [];
    foreach (func_get_args() as $attributes) {
        if (empty($attributes)) {
            continue;
        }
        if (!is_array($attributes)) {
            if ($value = trim((string) $attributes)) {
                $html[] = ' '.$value;
            }
            continue;
        }
        if (isset($attributes['class'])) {
            $attributes['class'] = classnames($attributes['class']) ?: false; // false prevents class=""
        }
        if (isset($attributes['data']) && is_array($attributes['data'])) {
            foreach ($attributes['data'] as $name => $value) {
                $attributes['data-'.to_dashed($name)] = $value;
            }
            unset($attributes['data']);
        }
        foreach ($attributes as $name => $value) {
            if (is_array($value)) {
                if ($result = html_attributes($value)) {
                    $html[] = $result;
                }
            } elseif (null !== $value && false !== $value) {
                $html[] = ' '.strtolower($name).(true === $value ? '' : sprintf('="%s"', htmlentities($value)));
            }
        }
    }

    return implode($html);
}

is_assoc.php

<?php

function is_assoc($var, $allowEmpty = true) {
    if (!is_array($var)) {
        return false;
    }
    if (empty($var)) {
        return $allowEmpty;
    }
    // Fastest method I've seen so far.
    foreach (array_keys($var) as $idx => $key) {
        if ($key !== $idx) {
            return true;
        }
    }
    return false;
}

to_dashed.php

<?php

function to_dashed($str, $upper = false) {
    $str = uncamel($str, '-', $upper ? CASE_UPPER : CASE_LOWER);
    return preg_replace('/[^[:alnum:]]+/', '-', $str);
}

uncamel.php

<?php

function uncamel($strIn, $delim = ' ', $case = null) {
    static $rxSplit = '/
        (?<=[0-9])    (?=[a-zA-Z]) | # split at number-letter
        (?<=[a-zA-Z]) (?=[0-9])    | # split at letter-number
        (?<=[a-z])    (?=[A-Z])    | # split at lower-UPPER
        (?<=[A-Z])    (?=[A-Z][a-z]) # split at UPPER-Capitalized
    /x';

    $strOut = preg_replace($rxSplit, $delim, trim($strIn));

    switch ($case) {
        case CASE_LOWER: return strtolower($strOut);
        case CASE_UPPER: return strtoupper($strOut);
        default:         return $strOut;
    }
}