Converting the code to typescript, making validators more type-safe

src/lib/extension/transporting/validators.ts

@@ -1,9 +1,46 @@
+import type StorageEntity from "$lib/extension/base/StorageEntity";
+
+/**
+ * Base information on the object which should be present on every entity.
+ */
+interface BaseImportableObject {
+  /**
+   * Numeric version of the entity for upgrading.
+   */
+  v: number;
+  /**
+   * Unique ID of the entity.
+   */
+  id: string;
+}
+
+/**
+ * Utility type which combines base importable object and the entity type interfaces together. It strips away any types
+ * defined for the properties, since imported object can not be trusted and should be type-checked by the validators.
+ */
+type ImportableObject<EntityType extends StorageEntity> = { [ObjectKey in keyof BaseImportableObject]: any }
+  & { [SettingKey in keyof EntityType["settings"]]: any };
+
+/**
+ * Function for validating the entities.
+ * @todo Probably would be better to replace the throw-catch method with some kind of result-error returning type.
+ *   Errors are only properly definable in the JSDoc.
+ */
+type ValidationFunction<EntityType extends StorageEntity> = (importedObject: ImportableObject<EntityType>) => void;
+
+/**
+ * Mapping of validation functions for all entities present in the extension. Key is a name of entity and value is a
+ * function which throws an error when validation is failed.
+ */
+type EntitiesValidationMap = {
+  [EntityKey in keyof App.EntityNamesMap]?: ValidationFunction<App.EntityNamesMap[EntityKey]>;
+};
+
 /**
  * Map of validators for each entity. Function should throw the error if validation failed.
- * @type {Map<keyof App.EntityNamesMap|string, ((importedObject: Object) => void)>}
  */
-const entitiesValidators = new Map([
-  ['profiles', importedObject => {
+const entitiesValidators: EntitiesValidationMap = {
+  profiles: importedObject => {
     if (importedObject.v !== 1) {
       throw new Error('Unsupported version!');
     }
@@ -18,22 +55,20 @@ const entitiesValidators = new Map([
     ) {
       throw new Error('Invalid profile format detected!');
     }
-  }]
-])
+  }
+};
 
 /**
  * Validate the structure of the entity.
- * @param {Object} importedObject Object imported from JSON.
- * @param {string} entityName Name of the entity to validate. Should be loaded from the entity class.
+ * @param importedObject Object imported from JSON.
+ * @param entityName Name of the entity to validate. Should be loaded from the entity class.
  * @throws {Error} Error in case validation failed with the reason stored in the message.
  */
-export function validateImportedEntity(importedObject, entityName) {
-  if (!entitiesValidators.has(entityName)) {
+export function validateImportedEntity(importedObject: any, entityName: string) {
+  if (!entitiesValidators.hasOwnProperty(entityName)) {
     console.error(`Trying to validate entity without the validator present! Entity name: ${entityName}`);
     return;
   }
 
-  entitiesValidators
-    .get(entityName)
-    .call(null, importedObject);
+  entitiesValidators[entityName as keyof EntitiesValidationMap]!.call(null, importedObject);
 }