Adding single quote to Snowflake variable in Javascript Stored Procedure

I am trying to add single quote around the string and assign it to variable in a Snowflake Stored Procedure. But the value is returning as DEFAULT_STR as is.

var DEFAULT_STR = 'UNKNOWN'

var VAL_LIST = 'EMP_ID'

VAL_LIST = VAL_LIST +" "+ "'`${DEFAULT_STR}`'" + ','+ '"SYSTEM"';

Error Message:

SQL compilation error: error line 1 at position 183 invalid identifier '"${DEFAULT_STR}"' At Snowflake.execute

Please advise how I can achieve below expected output-

Expected output:

'EMP_ID UNKNOWN, SYSTEM"

>Solution :

This one should give you the output you want:

VAL_LIST = "'" + VAL_LIST +" "+ DEFAULT_STR + "," + "SYSTEM'";

The output of VAL_LIST is:

'EMP_ID UNKNOWN,SYSTEM'