Modern JavaScript from the Beginning - Second Edition - Maps

The video tutorial introduces maps, a data structure added in ES2015, explaining their key-value pair nature. It covers how to create a map, add and retrieve data using set and get methods, and check for key existence with the has method. The tutorial also demonstrates deleting keys, iterating over maps with foreach, and converting maps to arrays. A practical example of using maps in a poll project is discussed, highlighting their utility in tracking poll answers and votes.

What is a key feature of Maps that differentiates them from objects in JavaScript?

• Maps can only use strings as keys.

• Maps allow any data type as keys.

• Maps are immutable.

• Maps do not store key-value pairs.

Which method is used to add a key-value pair to a Map?

• insert()

• push()

• add()

• set()

How can you check if a specific key exists in a Map?

• Using the find() method

• Using the has() method

• Using the exists() method

• Using the contains() method

What does the forEach method do when used with a Map?

• It converts the Map to an array.

• It iterates over each key-value pair in the Map.

• It deletes entries from the Map.

• It adds new entries to the Map.

Which method would you use to retrieve all keys from a Map?

• retrieveKeys()

• allKeys()

• keys()

• getKeys()

What is the purpose of the next() method when used with a Map iterator?

• To add a new entry to the Map

• To delete the current entry

• To reset the iterator

• To retrieve the next key-value pair

How can you convert a Map to an array in JavaScript?

• Using Array.from()

• Using the convert() method

• Using the map() method

• Using the toArray() method