Overhaul error handling for controllers

This change fixes various issues with the GET endpoints to return more
accurate error messages. It adds business logic error objects that are
returned in a union type in the controllers. This change should help
separate the business logic from the actual errors from upstream
services.

There may be required changes still with handling those upstream errors
via Promises. Integration tests should be added to verify issues.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/formats.ts b/src/formats.ts
index 59a966e..1b5a572 100644
--- a/src/formats.ts
+++ b/src/formats.ts
@@ -1,6 +1,8 @@
+import { InvalidReportDocumentError } from "./errors";
+
 export interface Format {
   // returns the coverage value as %: Number(90.0), Number(100.0), Number(89.5)
-  parse_coverage: (file: Document) => number;
+  parse_coverage: (file: Document) => number | InvalidReportDocumentError;
   match_color: (coverage: number, stage_1: number, stage_2: number) => string;
 }
 
@@ -35,7 +37,7 @@ const FormatsObj: FormatObj = {
       parse_coverage: (file: Document) => {
         const scripts = file.getElementsByTagName("script");
         if (scripts.length == 0) {
-          throw new Error("Invalid report document");
+          return new InvalidReportDocumentError();
         }
         const data = scripts[0].text;
         const accumFunc = (regex: RegExp) => {