DEAD END EXPERIMENT: this turned out to be an unviable approach, due to erasure removing all payload on Mu terms.
Direct interop with the ASTs of parsed Typedefs terms from PureScript.
The JavaScript generated by Idris needs preprocessing:
- Replace 
letbyvar(downgrade to ES5) - Remove shebang and wrapper nullary function
 - Add 
exports.deserialize0 =tofunction Main__deserialize0 
npm i
npm run test