You can do this by prepending the line with space characters, instead of using backticks:

var str = "Some \        //has six spaces

vs

var str = "Some \ //does not have a space

But I'm not sure how to do this within a backtick code block.

You can do this by prepending the line with space characters, instead of using backticks.

The following line should end with 6 spaces

var str = "Some \      

vs

var str = "Some \ //does not have a space

But I'm not sure how to do this within a backtick code block.