BigQuery UDF & String.prototype.indexOf()

Question

I'm trying to use String.prototype.indexOf() in a BigQuery UDF to check if one String contains another ie use basic JavaScript.

But it gives me this error:

What am I doing wrong?

Answer 1

I didn't take into consideration that my incoming table row in BigQuery might have null values.

Easy fix by just checking s :

function decodeHelper(s) {
  if(s){
      if(s.indexOf("foo") > -1){
         return "true";
      }else{
         return "false";
      }
  }
}

Answer 2

Depends on how you then deal with result of decodeHelper, you might consider below option

function decodeHelper(s) {
  if(s){
      if(s.indexOf("b") > -1){
         return "true";
      }else{
         return "false";
      }
  }else{
      return "false";
  }  
}