How to increment a value in a JavaScript object?

Question

var map = {};
map[key] = value;

How can I

• assign value 1 if key does not yet exist in the object
• increment the value by 1 if it

Answer 1

It would be better if you convert array's value into integer and increment it. It will be robust code. By default array's value is string. so in case you do not convert it to integer then it might not work cross browser.

if (map[key] == null) map[key] = 0;
map[key] = parseInt(map[key])+1;