Again, not sure if this is a bug, and/or if it is an issue with the arvados cwl runner or cwl in general.

When I try to use certain str methods sch as str.includes in a cwl script (as part of Expression Tool) it doesn't work and stops running.

I narrowed it down and cut and pasted a simple example from a javascript doc page

var str = "Hello world, welcome to the universe.";
var n = str.includes("world");