javascript hashmap one line modify or create

Question

I want to know if there is a clean way to modify a value in a hashmap or create it if it doesn't exist without doing an if block. Example of what i'm currently doing

let dict = {}
if(dict['key']){
 dict['key'] += 1
} else {
 dict['key'] = 1
}

Want to know if there is a cleaner way to do what I did above.

Answer 1

Use dot notation, because the property isn't dynamic, and alternate dict.key with 0 before adding 1.

dict.key = (dict.key || 0) + 1;