packages/server: Return validation errors as JSON

packages/server/src/middleware/ErrorApiHandler.ts

@@ -1,6 +1,7 @@
-import {IMiddleware} from './IMiddleware'
 import {IErrorHandler} from './IErrorHandler'
 import {ILogger} from '../logger/ILogger'
+import {IMiddleware} from './IMiddleware'
+import {ValidationError} from '../validator'
 
 export class ErrorApiHandler implements IMiddleware {
   constructor(readonly logger: ILogger) {}
@@ -10,7 +11,17 @@ export class ErrorApiHandler implements IMiddleware {
       req.correlationId, err.stack)
     const statusCode = this.getStatus(err)
     res.status(statusCode)
-    res.end('An error occurred')
+    if (err instanceof ValidationError) {
+      res.json({
+        error: err.message,
+        errors: err.errors,
+      })
+      return
+    }
+    res.json({
+      error: 'An error occurred',
+      errors: [],
+    })
   }
 
   protected getStatus(err: Error): number {

packages/server/src/validator/ValidationError.ts

@@ -5,6 +5,7 @@ export class ValidationError extends Error {
   constructor(
     readonly errors: IValidationMessage[],
     message?: string,
+    readonly status: number = 400,
   ) {
     super(
       message