Map.prototype.has()

The has() method returns a boolean indicating whether an element with the specified key exists or not.

myMap.has(key)

key

The key of the element to test for presence in the Map object.

true if an element with the specified key exists in the Map object; otherwise false.

let myMap = new Map()
myMap.set('bar', "foo")

myMap.has('bar')   // returns true
myMap.has('baz')   // returns false

• Map
• Map.prototype.set()
• Map.prototype.get()