How to get a Value of a Map by its Key using JavaScript

Get a Value of a Map by a Key #

To get a value of a Map by a key, call the get() method, passing it the name of the key as a parameter, e.g. map.get('myKey'). The get method returns the value associated to the provided key.

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const map1 = new Map([
  ['country', 'Chile'],
  ['city', 'Santiago'],
]);

console.log(map1.get('country')); // 👉️ "Chile"

We used the Map.get method to get a value of a Map by a key.

The only parameter the method takes is the name of the key.

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const map1 = new Map([
  ['country', 'Chile'],
  ['city', 'Santiago'],
]);

console.log(map1.get('test')); // 👉️ undefined

If the keys in your Map are arrays or objects, you have to pass them to the get() method by reference.

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const obj = {country: 'Chile'};

const map1 = new Map([[obj, {city: 'Santiago'}]]);

console.log(map1.get(obj)); // 👉️ {city: 'Santiago'}

Further Reading #

• Get a Object's Key by its Value using JavaScript
• How to get the Length of an Object in JavaScript