fix: add asserts to needs (#327)

TypeScript 3.7 released support for assertion functions,
that support positive assertions
that can be evaluated in TypeScript.

This updates the `needs` function to export this behavior,
so it can be used.

Author: seebees

modules/material-management/src/needs.ts

@@ -16,7 +16,7 @@ export function needs(
   condition: any,
   errorMessage: string,
   Err: ErrorConstructor = Error
-) {
+): asserts condition {
   if (!condition) {
     throw new Err(errorMessage)
   }