diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index b4e4934f..1eecd5ac 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -293,7 +293,7 @@ jobs:
           node-version: 24
       - name: JS Type Check
         run: |
-          npx -p typescript tsc -p radicale/web/jsconfig.json
+          npx -y -p typescript@7.0.2 tsc -p radicale/web/jsconfig.json
 
   lint:
     name: Lint
diff --git a/radicale/web/internal_data/js/api/api.js b/radicale/web/internal_data/js/api/api.js
index 30ee46bb..41cfe8b8 100644
--- a/radicale/web/internal_data/js/api/api.js
+++ b/radicale/web/internal_data/js/api/api.js
@@ -28,7 +28,7 @@ import { create_request, to_error_message } from "./common.js";
  * Find the principal collection.
  * @param {?string} user
  * @param {?string} password
- * @param {function(?Collection, ?string):void} callback Returns result or error
+ * @param {(collection: Collection | null, error: string | null) => void} callback Returns result or error
  * @return {XMLHttpRequest}
  */
 export function get_principal(user, password, callback) {
@@ -81,7 +81,7 @@ export function get_principal(user, password, callback) {
  * @param {string} user
  * @param {?string} password
  * @param {Collection} collection
- * @param {function(?Array<Collection>, ?string):void} callback Returns result or error
+ * @param {(collections: Array<Collection> | null, error: string | null) => void} callback Returns result or error
  * @return {XMLHttpRequest}
  */
 export function get_collections(user, password, collection, callback) {
@@ -267,7 +267,7 @@ function _parse_collection(response, collection_href) {
  * @param {?string} password
  * @param {string} collection_href Must always start and end with /.
  * @param {File} file
- * @param {function(?string):void} callback Returns error or null
+ * @param {(error: string | null) => void} callback Returns error or null
  * @return {XMLHttpRequest}
  */
 export function upload_collection(user, password, collection_href, file, callback) {
@@ -291,7 +291,7 @@ export function upload_collection(user, password, collection_href, file, callbac
  * @param {string} user
  * @param {?string} password
  * @param {Collection} collection
- * @param {function(?string):void} callback Returns error or null
+ * @param {(error: string | null) => void} callback Returns error or null
  * @return {XMLHttpRequest}
  */
 export function delete_collection(user, password, collection, callback) {
@@ -315,7 +315,7 @@ export function delete_collection(user, password, collection, callback) {
  * @param {?string} password
  * @param {Collection} collection
  * @param {boolean} create
- * @param {function(?string):void} callback Returns error or null
+ * @param {(error: string | null) => void} callback Returns error or null
  * @return {XMLHttpRequest}
  */
 function create_edit_collection(user, password, collection, create, callback) {
@@ -394,7 +394,7 @@ function create_edit_collection(user, password, collection, create, callback) {
  * @param {string} user
  * @param {?string} password
  * @param {Collection} collection
- * @param {function(?string):void} callback Returns error or null
+ * @param {(error: string | null) => void} callback Returns error or null
  * @return {XMLHttpRequest}
  */
 export function create_collection(user, password, collection, callback) {
@@ -405,7 +405,7 @@ export function create_collection(user, password, collection, callback) {
  * @param {string} user
  * @param {?string} password
  * @param {Collection} collection
- * @param {function(?string):void} callback Returns error or null
+ * @param {(error: string | null) => void} callback Returns error or null
  * @return {XMLHttpRequest}
  */
 export function edit_collection(user, password, collection, callback) {
diff --git a/radicale/web/internal_data/js/api/sharing.js b/radicale/web/internal_data/js/api/sharing.js
index e83f440b..f5841348 100644
--- a/radicale/web/internal_data/js/api/sharing.js
+++ b/radicale/web/internal_data/js/api/sharing.js
@@ -41,9 +41,9 @@ import { create_request, to_error_message } from "./common.js";
  * @param {?string} password
  * @param {string} path
  * @param {object} body
- * @param {function(string):void} on_success
- * @param {?function():void} on_not_found
- * @param {?function(string):void} on_error
+ * @param {(response: string) => void} on_success
+ * @param {(() => void) | null} on_not_found
+ * @param {((error: string) => void) | null} on_error
  * @returns {XMLHttpRequest}
  */
 function call_sharing_api(
@@ -92,7 +92,7 @@ function call_sharing_api(
 /**
  * @param {string} user
  * @param {?string} password
- * @param {function(import("../api/sharing.js").ServerFeatures, ?string):void} callback
+ * @param {(features: import("../api/sharing.js").ServerFeatures, error: string | null) => void} callback
  */
 export function discover_server_features(user, password, callback) {
     call_sharing_api(
@@ -163,12 +163,12 @@ export const BDAY_CONFIG = Object.freeze([
 ]);
 
 export class ShareConfig {
+    /** @type {Record<string, any>} */
+    _values = {};
     /**
      * @param {ShareConfig|Record<string, any>} [data]
      */
     constructor(data = {}) {
-        /** @type {Record<string, any>} */
-        this._values = {};
         let rawData = data;
         if (data instanceof ShareConfig) {
             rawData = data._values;
@@ -310,8 +310,8 @@ export class Share {
         /** @type {number} */ this.TimestampUpdated = data.TimestampUpdated || 0;
         /** @type {Object<String, String>} */ this.Properties = data.Properties || {};
         /** @type {string} */ this.Conversion = data.Conversion || "";
-        /** @type {ShareActions} */ this._Actions = new ShareActions();
-        this.Actions = data.Actions || {};
+        /** @type {ShareActions} */
+        this._Actions = data.Actions instanceof ShareActions ? data.Actions : new ShareActions(data.Actions || {});
     }
 
     /**
@@ -351,7 +351,7 @@ export class Share {
  * @param {string} user
  * @param {?string} password
  * @param {?import("../models/collection.js").Collection} collection
- * @param {function(Array<Share>, ?string):void} callback
+ * @param {(shares: Array<Share>, error: string | null) => void} callback
  */
 export function reload_sharing_list(user, password, collection, callback) {
     let body = collection ? { PathMapped: decodeURIComponent(collection.href) } : {};
@@ -412,7 +412,7 @@ export function get_property_key(type, property) {
  * @param {string} user
  * @param {?string} password
  * @param {Share} share
- * @param {function(?string):void} callback
+ * @param {(error: string | null) => void} callback
  */
 export function add_share_by_token(
     user,
@@ -452,7 +452,7 @@ export function add_share_by_token(
  * @param {string} user
  * @param {?string} password
  * @param {Share} share
- * @param {function(?string):void} callback
+ * @param {(error: string | null) => void} callback
  */
 export function add_share_by_map(
     user,
@@ -494,7 +494,7 @@ export function add_share_by_map(
  * @param {string} user
  * @param {?string} password
  * @param {Share} share
- * @param {function(?string):void} callback
+ * @param {(error: string | null) => void} callback
  */
 export function delete_share_by_token(
     user,
@@ -526,7 +526,7 @@ export function delete_share_by_token(
  * @param {string} user
  * @param {?string} password
  * @param {Share} share
- * @param {function(?string):void} callback
+ * @param {(error: string | null) => void} callback
  */
 export function delete_share_by_map(
     user,
@@ -557,7 +557,7 @@ export function delete_share_by_map(
  * @param {string} user
  * @param {?string} password
  * @param {Share} share
- * @param {function(?string):void} callback
+ * @param {(error: string | null) => void} callback
  */
 export function update_share_by_token(
     user,
@@ -597,7 +597,7 @@ export function update_share_by_token(
  * @param {string} user
  * @param {?string} password
  * @param {Share} share
- * @param {function(?string):void} callback
+ * @param {(error: string | null) => void} callback
  */
 export function update_share_by_map(
     user,
@@ -641,7 +641,7 @@ export function update_share_by_map(
  * @param {string} user
  * @param {?string} password
  * @param {Share} share
- * @param {function(?string):void} callback
+ * @param {(error: string | null) => void} callback
  */
 export function update_incoming_share(
     user,
diff --git a/radicale/web/internal_data/js/scenes/CollectionsScene.js b/radicale/web/internal_data/js/scenes/CollectionsScene.js
index eee39a47..59a5cbf9 100644
--- a/radicale/web/internal_data/js/scenes/CollectionsScene.js
+++ b/radicale/web/internal_data/js/scenes/CollectionsScene.js
@@ -42,7 +42,7 @@ export class CollectionsScene {
      * @param {string} user
      * @param {?string} password
      * @param {Collection} principal_collection The princial collection
-     * @param {function(?string):void} onerror Called when an error occurs, before the
+     * @param {(error: string | null) => void} onerror Called when an error occurs, before the
      *                                   scene is popped.
      */
     constructor(user, password, principal_collection, onerror) {
diff --git a/radicale/web/internal_data/js/scenes/ShareCollectionScene.js b/radicale/web/internal_data/js/scenes/ShareCollectionScene.js
index 09683cf4..ddffc894 100644
--- a/radicale/web/internal_data/js/scenes/ShareCollectionScene.js
+++ b/radicale/web/internal_data/js/scenes/ShareCollectionScene.js
@@ -169,10 +169,10 @@ function update_share_list(user, password, collection, errorHandler) {
  * @param {import('../api/sharing.js').Share} share 
  * @param {HTMLElement} template 
  * @param {string} delete_label 
- * @param {function(string, string, import('../api/sharing.js').Share, function(?string):void):void} delete_action 
- * @param {function():void} [onDeleteSuccess] Optional extra callback after a successful delete.
+ * @param {(user: string, password: string | null, share: import('../api/sharing.js').Share, callback: (error: string | null) => void) => void} delete_action 
+ * @param {(() => void) | null} [onDeleteSuccess] Optional extra callback after a successful delete.
  */
-function add_share_row_node(user, password, collection, share, template, delete_label, delete_action, onDeleteSuccess) {
+function add_share_row_node(user, password, collection, share, template, delete_label, delete_action, onDeleteSuccess = null) {
   let pathortoken = share["PathOrToken"] || "";
   let node = /** @type {HTMLElement} */ (template.cloneNode(true));
   node.classList.remove("hidden");
diff --git a/radicale/web/internal_data/js/utils/collections_cache.js b/radicale/web/internal_data/js/utils/collections_cache.js
index d0b6e7cc..fa65ab0b 100644
--- a/radicale/web/internal_data/js/utils/collections_cache.js
+++ b/radicale/web/internal_data/js/utils/collections_cache.js
@@ -31,7 +31,7 @@ class CollectionsCache {
         this.server_features = null;
         /** @type {?XMLHttpRequest} */ this.collections_req = null;
         /** @type {?XMLHttpRequest} */ this.shares_req = null;
-        /** @type {?Array<{ onerror: function(string):void, displayData: function(Array<import("../api/sharing.js").Share>):void }>} */
+        /** @type {Array<{ onerror: (error: string) => void, displayData: (shares: Array<import("../api/sharing.js").Share>) => void }> | null} */
         this._sharing_callbacks = null;
     }
 
@@ -54,8 +54,8 @@ class CollectionsCache {
      * @param {string} user
      * @param {?string} password
      * @param {import("../models/collection.js").Collection} principal_collection
-     * @param {function(string):void} onerror
-     * @param {function(Array<import("../models/collection.js").Collection>, Array<import("../api/sharing.js").Share>, boolean):void} displayData
+     * @param {(error: string) => void} onerror
+     * @param {(collections: Array<import("../models/collection.js").Collection>, shares: Array<import("../api/sharing.js").Share>, loaded: boolean) => void} displayData
      */
     getChildCollections(user, password, principal_collection, onerror, displayData) {
         if (this.child_collections !== null && this.incoming_shares !== null) {
@@ -105,8 +105,8 @@ class CollectionsCache {
     /**
      * @param {string} user
      * @param {?string} password
-     * @param {function(string):void} onerror
-     * @param {function(Array<import("../api/sharing.js").Share>):void} displayData
+     * @param {(error: string) => void} onerror
+     * @param {(shares: Array<import("../api/sharing.js").Share>) => void} displayData
      */
     getSharingList(user, password, onerror, displayData) {
         if (this.incoming_shares !== null) {
@@ -140,8 +140,8 @@ class CollectionsCache {
     /**
      * @param {string} user
      * @param {?string} password
-     * @param {function(string):void} onerror
-     * @param {function(import("../api/sharing.js").ServerFeatures):void} displayData
+     * @param {(error: string) => void} onerror
+     * @param {(features: import("../api/sharing.js").ServerFeatures) => void} displayData
      */
     getServerFeatures(user, password, onerror, displayData) {
         if (this.server_features !== null) {
diff --git a/radicale/web/internal_data/js/utils/form_validator.js b/radicale/web/internal_data/js/utils/form_validator.js
index 6a5d3a94..989215f4 100644
--- a/radicale/web/internal_data/js/utils/form_validator.js
+++ b/radicale/web/internal_data/js/utils/form_validator.js
@@ -30,13 +30,13 @@ export class FormValidator {
      */
     constructor(error_handler) {
         this.error_handler = error_handler;
-        /** @type {Array<{field: HTMLInputElement, validation_method: function(): ?string}>} */
+        /** @type {Array<{field: HTMLInputElement, validation_method: () => string | null}>} */
         this.validation_methods = [];
     }
 
     /**
      * @param {HTMLInputElement} field
-     * @param {function(): ?string} validation_method
+     * @param {() => string | null} validation_method
      */
     addValidator(field, validation_method) {
         this.validation_methods.push({ field, validation_method });
@@ -67,7 +67,7 @@ export class FormValidator {
  * Validates that the input is not empty.
  * @param {HTMLInputElement} input 
  * @param {string} field_name 
- * @returns{function(): ?string}
+ * @returns {() => string | null}
  */
 export function validate_non_empty(input, field_name) {
     return () => {
@@ -83,7 +83,7 @@ export function validate_non_empty(input, field_name) {
  * @param {HTMLInputElement} input
  * @param {string} target
  * @param {string} field_name
- * @returns {function(): ?string}
+ * @returns {() => string | null}
  */
 export function validate_not_empty_or_equals(input, target, field_name) {
     return () => {
@@ -102,7 +102,7 @@ export function validate_not_empty_or_equals(input, target, field_name) {
  * Validates that the input is a valid HREF.
  * @param {HTMLInputElement} input
  * @param {string} field_name
- * @returns {function(): ?string}
+ * @returns {() => string | null}
  */
 export function validate_href(input, field_name) {
     return () => {
@@ -124,7 +124,7 @@ export function validate_href(input, field_name) {
  * Validates that the input is a valid color.
  * @param {HTMLInputElement} input
  * @param {string} field_name
- * @returns {function(): ?string}
+ * @returns {() => string | null}
  */
 export function validate_color(input, field_name) {
     return () => {
@@ -144,7 +144,7 @@ export function validate_color(input, field_name) {
  * @param {HTMLInputElement} input
  * @param {string} target
  * @param {string} field_name
- * @returns {function(): ?string}
+ * @returns {() => string | null}
  */
 export function validate_equals(input, target, field_name) {
     return () => {
@@ -160,7 +160,7 @@ export function validate_equals(input, target, field_name) {
  * Validates that at least one file is selected in a file input.
  * @param {HTMLInputElement} input
  * @param {string} field_name
- * @returns {function(): ?string}
+ * @returns {() => string | null}
  */
 export function validate_files(input, field_name) {
     return () => {
@@ -175,7 +175,7 @@ export function validate_files(input, field_name) {
  * Validates that the input is a valid integer (if not empty).
  * @param {HTMLInputElement} input
  * @param {string} field_name
- * @returns {function(): ?string}
+ * @returns {() => string | null}
  */
 export function validate_integer(input, field_name) {
     return () => {
diff --git a/radicale/web/internal_data/js/utils/misc.js b/radicale/web/internal_data/js/utils/misc.js
index 4444b892..ed39c5f0 100644
--- a/radicale/web/internal_data/js/utils/misc.js
+++ b/radicale/web/internal_data/js/utils/misc.js
@@ -156,7 +156,7 @@ export function get_element(node, selector) {
  *
  * @param {string} str
  * @param {number} max
- * @returns {str}
+ * @returns {string}
  */
 export function trim_to_max(str, max) {
     if (str.length > max - 2) {