.has()

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

Syntax

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

map.has(key);

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

Example

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.