Creating a simple extension Twig

It often happens that Twig does not have enough logic, and you need to quickly and easily extend the available output with new functions and filters. It’s very simple.

Create a module and a description of the service to it.

foobar.info.yml

name: FooBar
description: FooBar functionality
package: FooBar
type: module
core: 8.x
version: 8.x-1.0

foobar.services.yml

services:
  foobar.twig.fizzbuzz_extension:
    class: Drupal\foobar\Twig\Extension\FizzBuzz
    tags:
      - { name: twig.extension }

The last two lines just guarantee that FizzBuzz will be connected to Twig as an extension automatically.

FizzBuzz.php

getName method of FizzBuzz class must return unique value.

  public function getName() {
    return 'foobar_fizzbuzz';
  }

getFunctions and getFilters methods respectively define a new function and filter.

  public function getFunctions() {
    return [
      new \Twig_SimpleFunction('fizzbuzz', [$this, 'fizzBuzz'])
    ];
  }

  public function getFilters() {
    return [
      new \Twig_SimpleFilter('fizzbuzz', [$this, 'fizzBuzz']),
    ];
  }

with name fizzbuzz and callable [$this, ‘fizzBuzz’].

fizzBuzz method look like next code

  public function fizzBuzz($i) {
    $s = '';
    if ($i % 3 === 0) {
      $s .= 'Fizz';
    }
    if ($i % 5 === 0) {
      $s .= 'Buzz';
    }
    if ($i % 3 && $i % 5) {
      $s .= $i;
    }
    return $s;
  }

Now you can write

{% for i in 1..100 %}
  {{ i }} - {{ fizzbuzz(i) }} - {{ i|fizzbuzz }}
  <hr>
{% endfor %}

files