How to get a value from a Map in JavaScript
Łukasz Holeczek
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Retrieving values from a Map is a fundamental operation when working with key-value pairs in JavaScript.
As the creator of CoreUI, a widely used open-source UI library, I’ve relied on Maps extensively for managing component state and configuration over my 25 years of development experience.
The most efficient way to get a value from a Map is using the built-in get() method, which provides safe and predictable value retrieval.
This approach is standard across all modern JavaScript environments.
Use the get() method with the key to retrieve the corresponding value from a Map.
const userMap = new Map([
['name', 'John'],
['age', 30],
['role', 'developer']
])
const userName = userMap.get('name')
Here the get() method is called on the Map with the key 'name'. It returns the corresponding value 'John'. If the key doesn’t exist in the Map, get() returns undefined rather than throwing an error, making it safe to use without additional checks.
Best Practice Note:
This is the same pattern we use in CoreUI components to retrieve configuration values from Map-based registries.
Always check for undefined when working with keys that might not exist, or use has() before calling get() for critical operations.
