Drupal 8: Taxonomy Terms by Level | Boyle Software, Inc.

In Drupal 8, sometimes we have a lot of levels of taxonomy terms and we need to manage this in our code. For example, what if we need to get a specific level of the taxonomy?

So let’s imagine the following taxonomy tree:

Drinks
- Alcohol Drinks
  - Beer
  - Whiskey
  - Vodka
- Alcohol Free Drinks
  - Coca Cola
  - Pepsi
  - Milk
Fruits
- Fruits For Losing Weight
  - Apricot
  - Blackberrie
  - Cantaloupe
- Fruits For Dogs
  - Strawberry
  - Watermelon
  - Orange
Foods
- Fast Foods
  - Hamburger
  - Pizza
  - Hot Dog
- Healthy Foods
  - Almond
  - Oily Fish
  - Avocado

Below is a method to get only the 1st level:

// Load the taxonomy tree with special parameters.
$tree = \Drupal::entityTypeManager()->getStorage('taxonomy_term')->loadTree(
  'some_vocabulary', // This is your taxonomy term vocabulary (machine name).
  0,                 // This is "tid" of parent. Set "0" to get all.
  1,                 // Get only 1st level.
  TRUE               // Get full load of taxonomy term entity.
);
 
$result = [];
 
foreach ($tree as $term) {
  $result[] = $term->getTerm();
}
 
dsm($result);
 
[
  0 => 'Drinks',
  1 => 'Fruits',
  2 => 'Foods',
]

// Load the taxonomy tree with special parameters.

$tree = \Drupal::entityTypeManager()->getStorage('taxonomy_term')->loadTree(

'some_vocabulary', // This is your taxonomy term vocabulary (machine name).

0, // This is "tid" of parent. Set "0" to get all.

1, // Get only 1st level.

TRUE // Get full load of taxonomy term entity.

);

$result = [];

foreach ($tree as $term) {

$result[] = $term->getTerm();

}

dsm($result);

[

0 => 'Drinks',

1 => 'Fruits',

2 => 'Foods',

]

Get the 1st and 2nd levels:

// Load the taxonomy tree with special parameters.
$tree = \Drupal::entityTypeManager()->getStorage('taxonomy_term')->loadTree(
  'some_vocabulary', // This is your taxonomy term vocabulary (machine name).
  0,                 // This is "tid" of parent. Set "0" to get all.
  2,                 // Get terms from 1st and 2nd levels.
  TRUE               // Get full load of taxonomy term entity.
);
 
$result = [];
 
foreach ($tree as $term) {
  $result[] = $term->getTerm();
}
 
dsm($result);
 
[
  0 => 'Drinks',
  1 => 'Alcohol Drinks',
  2 => 'Alcohol Free Drinks',
  3 => 'Fruits',
  4 => 'Fruits For Losing Weight',
  5 => 'Fruits For Dogs',
  6 => 'Foods',
  7 => 'Fast Foods',
  8 => 'Healthy Foods',
]

// Load the taxonomy tree with special parameters.

$tree = \Drupal::entityTypeManager()->getStorage('taxonomy_term')->loadTree(

'some_vocabulary', // This is your taxonomy term vocabulary (machine name).

0, // This is "tid" of parent. Set "0" to get all.

2, // Get terms from 1st and 2nd levels.

TRUE // Get full load of taxonomy term entity.

);

$result = [];

foreach ($tree as $term) {

$result[] = $term->getTerm();

}

dsm($result);

[

0 => 'Drinks',

1 => 'Alcohol Drinks',

2 => 'Alcohol Free Drinks',

3 => 'Fruits',

4 => 'Fruits For Losing Weight',

5 => 'Fruits For Dogs',

6 => 'Foods',

7 => 'Fast Foods',

8 => 'Healthy Foods',

]

Get only the 2nd level:

// Get entity type manager service.
$manager = \Drupal::entityTypeManager()->getStorage('taxonomy_term');
// Load the taxonomy tree with special parameters.
$tree = $manager->loadTree(
  'some_vocabulary', // This is your taxonomy term vocabulary (machine name).
  0,                 // This is "tid" of parent. Set "0" to get all.
  2,                 // Get terms from 1st and 2nd levels.
  TRUE               // Get full load of taxonomy term entity.
);
 
$result = [];
 
foreach ($tree as $term) {
  // We get 1st and 2nd levels, also we check parents (only 2nd level has parents).
  if (!empty($manager->loadParents($term->id()))) {
    $result[] = $term->getTerm();
  }
}
 
dsm($result);
 
[
  0 => 'Alcohol Drinks',
  1 => 'Alcohol Free Drinks',
  2 => 'Fruits For Losing Weight',
  3 => 'Fruits For Dogs',
  4 => 'Fast Foods',
  5 => 'Healthy Foods',
]

// Get entity type manager service.

$manager = \Drupal::entityTypeManager()->getStorage('taxonomy_term');

// Load the taxonomy tree with special parameters.

$tree = $manager->loadTree(

'some_vocabulary', // This is your taxonomy term vocabulary (machine name).

0, // This is "tid" of parent. Set "0" to get all.

2, // Get terms from 1st and 2nd levels.

TRUE // Get full load of taxonomy term entity.

);

$result = [];

foreach ($tree as $term) {

// We get 1st and 2nd levels, also we check parents (only 2nd level has parents).

if (!empty($manager->loadParents($term->id()))) {

$result[] = $term->getTerm();

}

dsm($result);

[

0 => 'Alcohol Drinks',

1 => 'Alcohol Free Drinks',

2 => 'Fruits For Losing Weight',

3 => 'Fruits For Dogs',

4 => 'Fast Foods',

5 => 'Healthy Foods',

]

Get the 2nd and 3rd levels:

// Get entity type manager service.
$manager = \Drupal::entityTypeManager()->getStorage('taxonomy_term');
// Load the taxonomy tree with special parameters.
$tree = $manager->loadTree(
  'some_vocabulary', // This is your taxonomy term vocabulary (machine name).
  0,                 // This is "tid" of parent. Set "0" to get all.
  3,                 // Get terms from 1st, 2nd and 3rd levels.
  TRUE               // Get full load of taxonomy term entity.
);
 
$result = [];
 
foreach ($tree as $term) {
  // We get 2nd and 3rd levels, also we check parents (1st level does not have parents).
  if (!empty($manager->loadParents($term->id()))) {
    $result[] = $term->getTerm();
  }
}
 
dsm($result);
 
[
  0 => 'Alcohol Drinks',
  1 => 'Bear',
  2 => 'Whiskey',
  3 => 'Vodka',
  4 => 'Alcohol Free Drinks',
  5 => 'Coca Cola',
  6 => 'Pepsi',
  7 => 'Milk',
  8 => 'Fruits For Losing Weight',
  9 => 'Apricot',
  10 => 'Blackberrie',
  11 => 'Cantaloupe',
  12 => 'Fruits For Dogs',
  13 => 'Strawberry',
  14 => 'Watermelon',
  15 => 'Orange',
  16 => 'Fast Foods',
  17 => 'Hamburger',
  18 => 'Pizza',
  19 => 'Hot Dog',
  20 => 'Healthy Foods',
  21 => 'Almond',
  22 => 'Oily Fish',
  23 => 'Avocado',
)

// Get entity type manager service.

$manager = \Drupal::entityTypeManager()->getStorage('taxonomy_term');

// Load the taxonomy tree with special parameters.

$tree = $manager->loadTree(

'some_vocabulary', // This is your taxonomy term vocabulary (machine name).

0, // This is "tid" of parent. Set "0" to get all.

3, // Get terms from 1st, 2nd and 3rd levels.

TRUE // Get full load of taxonomy term entity.

);

$result = [];

foreach ($tree as $term) {

// We get 2nd and 3rd levels, also we check parents (1st level does not have parents).

if (!empty($manager->loadParents($term->id()))) {

$result[] = $term->getTerm();

}

dsm($result);

[

0 => 'Alcohol Drinks',

1 => 'Bear',

2 => 'Whiskey',

3 => 'Vodka',

4 => 'Alcohol Free Drinks',

5 => 'Coca Cola',

6 => 'Pepsi',

7 => 'Milk',

8 => 'Fruits For Losing Weight',

9 => 'Apricot',

10 => 'Blackberrie',

11 => 'Cantaloupe',

12 => 'Fruits For Dogs',

13 => 'Strawberry',

14 => 'Watermelon',

15 => 'Orange',

16 => 'Fast Foods',

17 => 'Hamburger',

18 => 'Pizza',

19 => 'Hot Dog',

20 => 'Healthy Foods',

21 => 'Almond',

22 => 'Oily Fish',

23 => 'Avocado',

)

Get only the last level:

// Get entity type manager service.
$manager = \Drupal::entityTypeManager()->getStorage('taxonomy_term');
// Load the taxonomy tree with special parameters.
$tree = $manager->loadTree(
  'some_vocabulary', // This is your taxonomy term vocabulary (machine name).
  0,                 // This is "tid" of parent. Set "0" to get all tree.
  NULL,              // Get all levels.
  TRUE               // Get full load of taxonomy term entity.
);
 
$result = [];
 
foreach ($tree as $term) {
  if (empty($manager->loadChildren($term->id()))) {
    $result[] = $term->getTerm();
  }
}
 
dsm($result);
 
[
  1 => 'Bear',
  2 => 'Whiskey',
  3 => 'Vodka',
  4 => 'Coca Cola',
  5 => 'Pepsi',
  6 => 'Milk',
  7 => 'Apricots',
  8 => 'Blackberrie',
  9 => 'Cantaloupe',
  10 => 'Strawberry',
  11 => 'Watermelon',
  12 => 'Orange',
  13 => 'Hamburger',
  14 => 'Pizza',
  15 => 'Hot Dog',
  16 => 'Almonds',
  17 => 'Oily Fish',
  18 => 'Avocado',
]

// Get entity type manager service.

$manager = \Drupal::entityTypeManager()->getStorage('taxonomy_term');

// Load the taxonomy tree with special parameters.

$tree = $manager->loadTree(

'some_vocabulary', // This is your taxonomy term vocabulary (machine name).

0, // This is "tid" of parent. Set "0" to get all tree.

NULL, // Get all levels.

TRUE // Get full load of taxonomy term entity.

);

$result = [];

foreach ($tree as $term) {

if (empty($manager->loadChildren($term->id()))) {

$result[] = $term->getTerm();

}

dsm($result);

[

1 => 'Bear',

2 => 'Whiskey',

3 => 'Vodka',

4 => 'Coca Cola',

5 => 'Pepsi',

6 => 'Milk',

7 => 'Apricots',

8 => 'Blackberrie',

9 => 'Cantaloupe',

10 => 'Strawberry',

11 => 'Watermelon',

12 => 'Orange',

13 => 'Hamburger',

14 => 'Pizza',

15 => 'Hot Dog',

16 => 'Almonds',

17 => 'Oily Fish',

18 => 'Avocado',

]

I would like add a note about using the entity type manager service. Actually, this applies to all Drupal services… In the above examples we got this service by static method via a Drupal object:

// Get entity type manager service.
$manager = \Drupal::entityTypeManager()->getStorage('taxonomy_term');

1 2	// Get entity type manager service. $manager = \Drupal::entityTypeManager()->getStorage('taxonomy_term');

But the better way to get this service is to use Dependency Injection.