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JavaScript Map get( ) Method

  • Last Updated : 24 Nov, 2021

The Map.get() method in JavaScript is used for returning a specific element among all the elements which are present in a map. The Map.get() method takes the key of the element to be returned as an argument and returns the element which is associated with the specified key passed as an argument. If the key passed as an argument is not present in the map, then Map.get() method returns undefined. The Map.get() method is used to get a specific element among all the elements which are present in a map.

Syntax:

mapObj.get(key)

Parameter Value:

  • key: It is the key of the element of the map which has to be returned.

Return Value: The Map.get() method returns the element which is associated with the specified key passed as an argument or undefined if the key passed as an argument is not present in the map.

The examples below illustrate the get() method:

Example 1: This example describes the Map() method to create the map object that contains the [key, value] pair to the map & displays the element that is associated with the specific key using the Map.get() method.

javascript




<script>
  // Creating a map object
  var myMap = new Map();
 
  // Adding [key, value] pair to the map
  myMap.set(0, 'GeeksforGeeks');
 
  // Displaying the element which is associated with
  // the key '0' using Map.get() method
  document.write(myMap.get(0));
</script>

Output:

"GeeksforGeeks"

Example 2: This example describes the Map() method to create the map object that contains the multiple [key, value] pair to the map & displays the element that is associated with the specific key using the Map.get() method.

Javascript




<script>
  // Creating a map object
  var myMap = new Map();
 
  // Adding [key, value] pair to the map
  myMap.set(0, 'GeeksforGeeks');
  myMap.set(1, 'is an online portal');
  myMap.set(2, 'for geeks');
 
  // Displaying the elements which are associated with the keys '0', '2'
  // and '4' using Map.get() method
  document.write(myMap.get(0),"</br>");
  document.write(myMap.get(2),"</br>");
  document.write(myMap.get(4),"</br>");
</script>

Output:

"GeeksforGeeks"
"for geeks"
undefined

Exceptions:

  • If the variable is not of the Map type then the Map.get() operation throws a TypeError.
  • If the index specified in the Map.get() function doesn’t belong to the [key, value] pairs of a map, the Map.get() function returns undefined.

Differences between Objects and Maps in JavaScript: Both of these data structures are similar in many ways such as both are used to store values using keys, allowing retrieval of those values using keys, deletion of keys, and verifying whether a key holds any value or not. However, there are quite significant differences between Objects and Maps in JavaScript which make the usage of maps a better and more preferable option in many cases.

  • The keys used in maps can be any type of values such as functions, objects, etc whereas the keys in objects are limited to symbols and strings.
  • The size of a map can be known easily by using the size property but while dealing with objects, the size has to be determined manually.
  • A Map should be preferred in cases where the requirement involves frequent addition and removal of [key, value] pairs because a map is an iterative data type and can be directly iterated whereas iterating an Object requires obtaining its keys in a specific manner.

Supported Browsers:

  • Google Chrome 38.0
  • Microsoft Edge 12.0
  • Firefox 13.0
  • Internet Explorer 11.0
  • Opera 25.0
  • Safari 8.0


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