If it isn’t re-usable, it probably wasn’t usable in the first place

Please think about this.  Don't focus on making your code work, focus on making it usable.  To do this, you need to focus on making it RE-usable.  Until you have that third or tenth or hundredth use case working smoothly, you're not done.  And in fact, the use cases you think work might actually be buggy too.