Hey guys, I’m compiling a lib that is supposed to be consumed by TypeScript. How do I export a `Long...

# javascript

[salomonbrys]

Hey guys,
I’m compiling a lib that is supposed to be consumed by TypeScript.
How do I export a Long to JS with the IR compiler ???

@JsExport
fun long(): Long = 0x12_34_56_78_9A_BC_DE_F0

Calling this long function with typescript returns the following object: Long { _low: -1698898192, _high: 305419896 }

Casting to int does NOT do the trick as the compiler overflows :

@JsExport
fun int(): Int = 0x12_34_56_78_9A_BC_DE_F0.toInt()

Calling this int function with typescript returns a negative number: -1698898192

How can I export a Long ?

[hfhbd]

JavaScript does not have a Long implementation.

[spand]

Often a double is good enough. It can represent intergers up to ~54bits

[salomonbrys]

That’s untrue.
JavaScript can natively handle 8 bytes numbers, such as 9223372036854775 , which is way over Int.MAX_VALUE.
Running in node:

let n = 9223372036854775
n = n + 1

Gives the correct value

[spand]

@salomonbrys Javascript Number type is a double (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number)

[salomonbrys]

Thanks Johannes, that’s exactly what I needed 😉