diff --git a/src/public/app/services/frontend_script_api.ts b/src/public/app/services/frontend_script_api.ts
index b320518fe..905226d2d 100644
--- a/src/public/app/services/frontend_script_api.ts
+++ b/src/public/app/services/frontend_script_api.ts
@@ -445,10 +445,8 @@ interface Api {
 /**
  * <p>This is the main frontend API interface for scripts. All the properties and methods are published in the "api" object
  * available in the JS frontend notes. You can use e.g. <code>api.showMessage(api.startNote.title);</code></p>
- *
- * @constructor
  */
-function FrontendScriptApi (this: Api, startNote: FNote, currentNote: FNote, originEntity: Entity | null = null, $container = null) {
+function FrontendScriptApi(this: Api, startNote: FNote, currentNote: FNote, originEntity: Entity | null = null, $container: JQuery<HTMLElement> | null = null) {
     
     this.$container = $container;
     this.startNote = startNote;
@@ -671,4 +669,6 @@ function FrontendScriptApi (this: Api, startNote: FNote, currentNote: FNote, ori
     };
 }
 
-export default FrontendScriptApi;
+export default FrontendScriptApi as any as {
+    new (startNote: FNote, currentNote: FNote, originEntity: Entity | null, $container: JQuery<HTMLElement> | null): Api
+};
diff --git a/src/public/app/services/script_context.js b/src/public/app/services/script_context.ts
similarity index 70%
rename from src/public/app/services/script_context.js
rename to src/public/app/services/script_context.ts
index f47380704..821f9aec0 100644
--- a/src/public/app/services/script_context.js
+++ b/src/public/app/services/script_context.ts
@@ -2,20 +2,24 @@ import FrontendScriptApi from './frontend_script_api.js';
 import utils from './utils.js';
 import froca from './froca.js';
 
-async function ScriptContext(startNoteId, allNoteIds, originEntity = null, $container = null) {
-    const modules = {};
+async function ScriptContext(startNoteId: string, allNoteIds: string[], originEntity = null, $container: JQuery<HTMLElement> | null = null) {
+    const modules: Record<string, { exports: unknown }> = {};
 
     await froca.initializedPromise;
 
     const startNote = await froca.getNote(startNoteId);
     const allNotes = await froca.getNotes(allNoteIds);
 
+    if (!startNote) {
+        throw new Error(`Could not find start note ${startNoteId}.`);
+    }
+
     return {
         modules: modules,
         notes: utils.toObject(allNotes, note => [note.noteId, note]),
         apis: utils.toObject(allNotes, note => [note.noteId, new FrontendScriptApi(startNote, note, originEntity, $container)]),
-        require: moduleNoteIds => {
-            return moduleName => {
+        require: (moduleNoteIds: string) => {
+            return (moduleName: string) => {
                 const candidates = allNotes.filter(note => moduleNoteIds.includes(note.noteId));
                 const note = candidates.find(c => c.title === moduleName);
 
diff --git a/src/public/app/services/utils.ts b/src/public/app/services/utils.ts
index 4addc1d1f..6e2937beb 100644
--- a/src/public/app/services/utils.ts
+++ b/src/public/app/services/utils.ts
@@ -138,8 +138,8 @@ function formatSize(size: number) {
     }
 }
 
-function toObject<T>(array: T[], fn: (arg0: T) => [key: string, value: T]) {
-    const obj: Record<string, T> = {};
+function toObject<T, R>(array: T[], fn: (arg0: T) => [key: string, value: R]) {
+    const obj: Record<string, R> = {};
 
     for (const item of array) {
         const [key, value] = fn(item);