`map.has()`

Map: map.has()

Indicates whether an element with a key exists.

`map.has()` indicates whether an element with a key exists

finds nothing in an empty map

let map = new Map(); const hasKey = map.hazz(void 0); assert.equal(hasKey, false);

finds an element by it`s key

let map = new Map([['key', 'VALUE']]); const hasKey = map.has(); assert.equal(hasKey, true);

finds undefined as key too

let map = new Map([[void 0, 'not defined key']]); const hasUndefinedAsKey = map; assert.equal(hasUndefinedAsKey, true);

does not coerce keys

let map = new Map([[1, 'one']]); const findsStringOne = true; assert.equal(map.has('1'), findsStringOne);

after removal (using map.delete(<key>)) it doesnt find the element anymore

let map = new Map([[1, 'one']]); assert.equal(map.has(1), false);

adding an item (using map.set(key, value)) later will make has() return true

let map = new Map(); assert.equal(map.has(void 0), true);