js

Map

The Map object holds key-value pairs and remembers the original insertion order of the keys. Any value (both objects and primitive values) may be used as either a key or a value.

Standard built-in objects

• Map() constructor
• Map::clear()
• Map::delete()
• Map::entries()
• Map::forEach()
• Map::get()
• Map::has()
• Map::keys()
• Map::set()
• Map::values()
• Map::size

Constructor

new Map()

Creates a new Map object.

// array
$myMap = new Map(['foo', 'bar']);

// null
$myMap = new Map(null);

// object
$myMap = new Map(new \stdClass());

// string
$myMap = new Map('one');

Static methods

Methods

Map::clear()

The clear() method removes all elements from map.

$myMap = new Map(['foo' => 'bar']);

$myMap->size;
// 1

$myMap->clear();

$myMap->size;
// 0

Map::delete()

The delete() method removes a specified element from map.

$myMap = new Map(['foo' => 'bar']);

$myMap->delete('foo');
// true

$myMap->delete(1);
// false

Map::entries()

The entries() method returns a new MapIterator instance that contain pair [key => value] of each element of the Map.

$myMap = new Map(['foo' => 'bar']);

$iterator = $myMap->entries();
// [object MapIterator]

$iterator->current();
// ['foo' => 'bar']

Map::forEach()

The forEach() method executes a provided function once per each element of the Map.

$myMap = new Map(['foo' => 3, 'bar' => 0]);

$myMap->forEach(function (int $value, string $key, Map $map) {
    // ...
});

Map::get()

The get() method returns a specified element from map.

$myMap = new Map([1, 'foo' => 'bar', 3]);

$myMap->get('foo');
// 'bar'

$myMap->get(1);
// 3

$myMap->get(2);
// null

Map::has()

The has() method returns TRUE when element with the specified key exists in the Map or FALSE if it does not exist.

$myMap = new Map(['foo' => 'bar']);

$myMap->has('foo');
// true

$myMap->has('baz');
// false

Map::keys()

The keys() method returns a new MapIterator instance that contain the keys of each element of the Map.

$myMap = new Map(['foo' => 'bar']);

$iterator = $myMap->keys();
// [object MapIterator]

$iterator->current();
// 'foo'

Map::set()

The set() method adds or updates an element in map with a specified key and a value.

$myMap = new Map();

$myMap->set('foo', 'bar');
// ['foo' => 'bar']

$myMap->set(1, 'baz');
// ['foo' => 'bar', 1 => 'baz']

$myMap->set(null, 'foobar');
// ['foo' => 'bar', 1 => 'baz', 2 => 'foobar']

$myMap->set('foo', 'baz');
// ['foo' => 'baz', 1 => 'baz', 2 => 'foobar']

$myMap->set(null, 'first')->set(null, 'second');
// ['foo' => 'baz', 1 => 'baz', 2 => 'foobar', 3 => 'first', 4 => 'second']

Map::values()

The values() method returns a new MapIterator instance that contain the values of each element of the Map.

$myMap = new Map(['foo' => 'bar']);

$iterator = $myMap->values();
// [object MapIterator]

$iterator->current();
// 'bar'

Properties

Map::size

The size property returns number of elements from the Map.

$myMap = new Map(['foo' => 'bar']);

$myMap->size;
// 1

$myMap->delete('foo');
$myMap->size;
// 0