Add missing API error class exports/imports

app/src/api/api.ts

@@ -2,6 +2,7 @@ import bodyParser from 'body-parser';
 import express from 'express';
 
 import * as editHistoryController from './controllers/editHistoryController';
+import { RequestParameterError, UserInputError } from './errors'; 
 import buildingsRouter from './routes/buildingsRouter';
 import extractsRouter from './routes/extractsRouter';
 import usersRouter from './routes/usersRouter';

app/src/api/errors.ts

@@ -5,13 +5,13 @@
  * https://stackoverflow.com/questions/41102060/typescript-extending-error-class
  */
 
-class UserInputError extends Error {
+export class UserInputError extends Error {
     constructor(message?: string) {
         super(message);
     }
 }
 
-class RequestParameterError extends UserInputError {
+export class RequestParameterError extends UserInputError {
     public paramName: string;
 
     constructor(message?: string) {
@@ -19,19 +19,19 @@ class RequestParameterError extends UserInputError {
     }
 }
 
-class ParamRequiredError extends RequestParameterError {
+export class ParamRequiredError extends RequestParameterError {
     constructor(message?: string) {
         super(message);
     }
 }
 
-class ParamOutOfBoundsError extends RequestParameterError {
+export class ParamOutOfBoundsError extends RequestParameterError {
     constructor(message?: string) {
         super(message);
     }
 }
 
-class ParamInvalidFormatError extends RequestParameterError {
+export class ParamInvalidFormatError extends RequestParameterError {
     constructor(message?: string) {
         super(message);
     }

app/src/api/parameters.ts

@@ -1,5 +1,7 @@
 import { strictParseInt } from '../parse';
 
+import { ParamInvalidFormatError, ParamRequiredError, RequestParameterError } from './errors';
+
 
 export function processParam<T>(params: object, paramName: string, processingFn: (x: string) => T, required: boolean = false) {
     const stringValue = params[paramName];
@@ -37,4 +39,6 @@ export function checkRegexParam(param: string, regex: RegExp): string {
     if(param.match(regex) == undefined) {
         throw new ParamInvalidFormatError(`Invalid format: does not match regular expression ${regex}`);
     }
+    
+    return param;
 }