PHP helper functions for creating HTML tags

html-helper.php

<?php
namespace HtmlHelpers;

function el(string $tag, array $atts = [], array $content = []) {
  if (empty($content)) {
    return '<' . join(' ', array_filter([$tag, at($atts)])) . ' />';
  }

  return '<' . join(' ', array_filter([$tag, at($atts)])) . '>' . join($content) . '</' . $tag . '>';
}

function at(array $atts = []) {
  $atts = array_filter($atts);
  
  return join(' ', array_map(function ($attribute, $value) {
    if ($value === true) {
      return $attribute;
    }

    if (is_int($value)) {
      return $attribute . '=' . $value;
    }

    if (is_array($value) || is_object($value)) {
      $value = json_encode($value);
    }

    return $attribute . '="' . htmlspecialchars($value, ENT_QUOTES) . '"';
  }, array_keys($atts), array_values($atts)));
}

$html = el('html', [], [
  el('head', [], [
    el('title', [], ['Some example title']),
    el('meta', [
      'content-type' => 'text/html;charset=utf-8',
    ]),
  ]),
  el('body', ['class' => 'body'], [
    el('h1', [], ['Some example header']),
    el('p', [], [
      'Some example paragraph',
      el('br'),
      'Other line',
    ]),
  ]),
]);