Question

I guess this problem is common for CoffeScript and JavaScript. In my CoffeeScript script I receive a number like 606.0 over a websocket. Thus it comes as a string, being extracted from the JSON that arrived from the host. Now I want to work with this number, say, add something to it like:

# @x is the number presented as a string
@xx = @x + 100
console.log("res=" + @xx)

and what I get is:

res=606.0100

So it gets added as a string! And if I change the code a little, “saying” that 100 is float:

# @x is the number presented as a string
@xx = @x + 100.0
console.log("res=" + @xx)

The result is still the same.

My question is – how to explain to CoffeScript/JavaScript that this is a number, and not a string?

Answer 1

To cast number from string just prepend a +:

n = '100'
alert n + 1 # 1001
alert +n + 1 # 101

http://jsfiddle.net/elclanrs/d77uq/