I pass a variable to ejs but still throw Uncaught ReferenceError why?

Question

I pass a productId but still get Reference error in ejs why is that happening?

Script in frontend:

<script> 
(typeof <%= productId %> != "undefined" ? productId: -1 )
</script>

Another Try:

if(typeof <%= productId %> != "undefined"){
  const productId = productId
} else{
  const productId = -1
}

Error message:

fall-look:194 Uncaught ReferenceError: look is not defined
    at fall-look:194:14

Catched error with try- catch:

Where error happened:

We can clearly see a productId is defined but still throw productId is not defined error why is this happened?