Introduction to Web Assembly

By Jem Young

Writing Web Assembly

Let's write something a bit more complicated. Create an equivalent function in Web Assembly:

function example(n) {
  if (n === 2) {
    return n * 2;
  }

  if (n === 3) {
    return n * 3;
  }

  return n * n;
}

The equivalent Web Assembly function is a bit more...verbose

 (func $example (param $0 i32) (result i32)
  get_local $0
  i32.const 2
  i32.eq
  if
   get_local $0
   i32.const 2
   i32.mul
   return
  end
  get_local $0
  i32.const 3
  i32.eq
  if
   get_local $0
   i32.const 3
   i32.mul
   return
  end
  get_local $0
  get_local $0
  i32.mul
 )

As we can see writing Web Assembly by hand isn't terribly practical. Fortunately we have AssemblyScript.