diff --git a/src/scripts/shared.ts b/src/scripts/shared.ts
index bdae569..2c5e343 100644
--- a/src/scripts/shared.ts
+++ b/src/scripts/shared.ts
@@ -13,6 +13,8 @@ import Session from "./classes/session.js";
 
 // Types declaration
 export type DictType = { [n: number]: string; };
+type KeyPrefixesType = "engines" | "statuses" | "tags" | "others";
+type PrefixesType = { [key in KeyPrefixesType]: DictType }
 
 /**
  * Class containing variables shared between modules.
@@ -26,7 +28,7 @@ export default abstract class Shared {
     /**
      * List of platform prefixes and tags.
      */
-    static _prefixes: {[s: string]: DictType} = {}
+    static _prefixes: PrefixesType = {} as PrefixesType;
     /**
      * Logger object used to write to both file and console.
      */
@@ -71,7 +73,7 @@ export default abstract class Shared {
     //#endregion Getters
 
     //#region Setters
-    static setPrefixPair(key: string, val: DictType): void {
+    static setPrefixPair(key: KeyPrefixesType, val: DictType): void {
         this._prefixes[key] = val;
     }