diff --git a/src/model/types.ts b/src/model/types.ts
index 33b1a98..e04f565 100644
--- a/src/model/types.ts
+++ b/src/model/types.ts
@@ -1,43 +1,48 @@
-export enum TimeUnit {
-  Minutes = "minutes",
-  Hours = "hours",
-  Days = "days",
-  Weeks = "weeks",
-  Months = "months",
-  Percent = "percent",
-}
+export const TimeUnit = {
+  Minutes: "minutes",
+  Hours: "hours",
+  Days: "days",
+  Weeks: "weeks",
+  Months: "months",
+  Percent: "percent",
+} as const;
+export type TimeUnit = (typeof TimeUnit)[keyof typeof TimeUnit];
 
-export enum RelationType {
-  FinishToStart = "FS",
-  StartToStart = "SS",
-  FinishToFinish = "FF",
-  StartToFinish = "SF",
-}
+export const RelationType = {
+  FinishToStart: "FS",
+  StartToStart: "SS",
+  FinishToFinish: "FF",
+  StartToFinish: "SF",
+} as const;
+export type RelationType = (typeof RelationType)[keyof typeof RelationType];
 
-export enum ResourceType {
-  Material = "Material",
-  Work = "Work",
-  Cost = "Cost",
-}
+export const ResourceType = {
+  Material: "Material",
+  Work: "Work",
+  Cost: "Cost",
+} as const;
+export type ResourceType = (typeof ResourceType)[keyof typeof ResourceType];
 
-export enum ConstraintType {
-  AsSoonAsPossible = "ASAP",
-  AsLateAsPossible = "ALAP",
-  MustStartOn = "MSO",
-  MustFinishOn = "MFO",
-  StartNoEarlierThan = "SNET",
-  StartNoLaterThan = "SNLT",
-  FinishNoEarlierThan = "FNET",
-  FinishNoLaterThan = "FNLT",
-}
+export const ConstraintType = {
+  AsSoonAsPossible: "ASAP",
+  AsLateAsPossible: "ALAP",
+  MustStartOn: "MSO",
+  MustFinishOn: "MFO",
+  StartNoEarlierThan: "SNET",
+  StartNoLaterThan: "SNLT",
+  FinishNoEarlierThan: "FNET",
+  FinishNoLaterThan: "FNLT",
+} as const;
+export type ConstraintType = (typeof ConstraintType)[keyof typeof ConstraintType];
 
-export enum Priority {
-  Lowest = 100,
-  Low = 250,
-  Medium = 500,
-  High = 750,
-  Highest = 1000,
-}
+export const Priority = {
+  Lowest: 100,
+  Low: 250,
+  Medium: 500,
+  High: 750,
+  Highest: 1000,
+} as const;
+export type Priority = (typeof Priority)[keyof typeof Priority];
 
 export type { ProjectProperties } from "../schema/project.ts";
 export type { WorkingTimeRange, CalendarWeekDay, CalendarException } from "../schema/calendar.ts";