Returns a boolean reflecting whether an entry with a given key exists in a Map object.


The .has() method accepts a key as a parameter:


If the key exists in map, .has() returns true. Otherwise, it returns false.


Checking whether a key is in the fruits Map object can be done using the .has() method:

const fruits = new Map([
['Apples', 5],
['Oranges', 8],
console.log(fruits.has('Apples')); // Output: true
console.log(fruits.has('Bananas')); // Output: false

The first .has() statement checks that there are 'Apples' in fruits, which returns true. The second statement finds that there are no 'Bananas' in fruits and false is returned.

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