Map: map.has()

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

• finds nothing in an empty map
• finds an element by it`s key
• finds undefined as key too
• does not coerce keys
• after removal (using map.delete(<key>)) it doesnt find the element anymore
• adding an item (using map.set(key, value)) later will make has() return true

Links

video A video (15min) documenting how this kata was created.