Think this is caused by the class LRUCache that alos is a namespace. This gets the compiler confused.
node_modules/coap/dist/lib/server.d.ts:11:8 - error TS1259: Module '"coap-service/node_modules/@types/lru-cache/index"' can only be default-imported using the 'esModuleInterop' flag
11 import LRUCache from 'lru-cache';
~~~~~~~~
node_modules/@types/lru-cache/index.d.ts:193:1
193 export = LRUCache;
~~~~~~~~~~~~~~~~~~
This module is declared with 'export =', and can only be used with a default import when using the 'esModuleInterop' flag.