diff --git a/src/becca/entities/abstract_becca_entity.ts b/src/becca/entities/abstract_becca_entity.ts
index 471cbf47f..519a4327f 100644
--- a/src/becca/entities/abstract_becca_entity.ts
+++ b/src/becca/entities/abstract_becca_entity.ts
@@ -104,13 +104,14 @@ abstract class AbstractBeccaEntity<T extends AbstractBeccaEntity<T>> {
     /**
      * Saves entity - executes SQL, but doesn't commit the transaction on its own
      */
-    save(): this {
+    // FIXME: opts not used but called a few times, maybe should be used by derived classes or passed to beforeSaving.
+    save(opts?: {}): this {
         const constructorData = (this.constructor as unknown as ConstructorData<T>);
         const entityName = constructorData.entityName;
         const primaryKeyName = constructorData.primaryKeyName;
 
         const isNewEntity = !(this as any)[primaryKeyName];
-
+        
         this.beforeSaving();
 
         const pojo = this.getPojoToSave();
diff --git a/src/becca/entities/battachment.ts b/src/becca/entities/battachment.ts
index 84f7de5c1..a5fc02698 100644
--- a/src/becca/entities/battachment.ts
+++ b/src/becca/entities/battachment.ts
@@ -45,7 +45,7 @@ class BAttachment extends AbstractBeccaEntity<BAttachment> {
     blobId?: string;
     isProtected?: boolean;
     dateModified?: string;
-    utcDateScheduledForErasureSince?: string;
+    utcDateScheduledForErasureSince?: string | null;
     /** optionally added to the entity */
     contentLength?: number;
     isDecrypted?: boolean;
@@ -126,8 +126,8 @@ class BAttachment extends AbstractBeccaEntity<BAttachment> {
         }
     }
 
-    getContent(): string | Buffer {
-        return this._getContent();
+    getContent(): Buffer {
+        return this._getContent() as Buffer;
     }
 
     setContent(content: any, opts: ContentOpts) {
@@ -170,6 +170,11 @@ class BAttachment extends AbstractBeccaEntity<BAttachment> {
 
         if (this.role === 'image' && parentNote.type === 'text') {
             const origContent = parentNote.getContent();
+            
+            if (typeof origContent !== "string") {
+                throw new Error(`Note with ID '${note.noteId} has a text type but non-string content.`);
+            }
+
             const oldAttachmentUrl = `api/attachments/${this.attachmentId}/image/`;
             const newNoteUrl = `api/images/${note.noteId}/`;
 
diff --git a/src/becca/entities/bnote.ts b/src/becca/entities/bnote.ts
index 0a3fb87f1..a39d62706 100644
--- a/src/becca/entities/bnote.ts
+++ b/src/becca/entities/bnote.ts
@@ -216,9 +216,8 @@ class BNote extends AbstractBeccaEntity<BNote> {
      * - changes in the note metadata or title should not trigger note content sync (so we keep separate utcDateModified and entity changes records)
      * - but to the user note content and title changes are one and the same - single dateModified (so all changes must go through Note and content is not a separate entity)
      */
-    // FIXME: original declaration was (string | Buffer), but everywhere it's used as a string.
-    getContent(): string {
-        return this._getContent() as string;
+    getContent() {
+        return this._getContent();
     }
 
     /**
@@ -226,7 +225,7 @@ class BNote extends AbstractBeccaEntity<BNote> {
     getJsonContent(): {} | null {
         const content = this.getContent();
 
-        if (!content || !content.trim()) {
+        if (typeof content !== "string" || !content || !content.trim()) {
             return null;
         }
 
@@ -243,7 +242,7 @@ class BNote extends AbstractBeccaEntity<BNote> {
         }
     }
 
-    setContent(content: string, opts: ContentOpts = {}) {
+    setContent(content: Buffer | string, opts: ContentOpts = {}) {
         this._setContent(content, opts);
 
         eventService.emit(eventService.NOTE_CONTENT_CHANGE, { entity: this });
@@ -661,7 +660,7 @@ class BNote extends AbstractBeccaEntity<BNote> {
      * @param name - relation name to filter
      * @returns all note's relations (attributes with type relation), including inherited ones
      */
-    getRelations(name: string): BAttribute[] {
+    getRelations(name?: string): BAttribute[] {
         return this.getAttributes(RELATION, name);
     }
 
@@ -1510,6 +1509,10 @@ class BNote extends AbstractBeccaEntity<BNote> {
         const oldNoteUrl = `api/images/${this.noteId}/`;
         const newAttachmentUrl = `api/attachments/${attachment.attachmentId}/image/`;
 
+        if (typeof parentContent !== "string") {
+            throw new Error("Unable to convert image note into attachment because parent note does not have a string content.");
+        }
+
         const fixedContent = utils.replaceAll(parentContent, oldNoteUrl, newAttachmentUrl);
 
         parentNote.setContent(fixedContent);
@@ -1611,7 +1614,7 @@ class BNote extends AbstractBeccaEntity<BNote> {
                 revisionAttachment.ownerId = revision.revisionId;
                 revisionAttachment.setContent(noteAttachment.getContent(), { forceSave: true });
 
-                if (this.type === 'text') {
+                if (this.type === 'text' && typeof noteContent === "string") {
                     // content is rewritten to point to the revision attachments
                     noteContent = noteContent.replaceAll(`attachments/${noteAttachment.attachmentId}`,
                         `attachments/${revisionAttachment.attachmentId}`);
@@ -1654,7 +1657,6 @@ class BNote extends AbstractBeccaEntity<BNote> {
             position
         });
 
-        content = content || "";
         attachment.setContent(content, {forceSave: true});
 
         return attachment;
diff --git a/src/becca/entities/rows.ts b/src/becca/entities/rows.ts
index 3bd4cae67..331f150df 100644
--- a/src/becca/entities/rows.ts
+++ b/src/becca/entities/rows.ts
@@ -13,7 +13,7 @@ export interface AttachmentRow {
     utcDateModified?: string;
     utcDateScheduledForErasureSince?: string;
     contentLength?: number;
-    content?: string;
+    content?: Buffer | string;
 }
 
 export interface RevisionRow {
@@ -69,9 +69,9 @@ export interface AttributeRow {
     noteId: string;
     type: AttributeType;
     name: string;
-    position: number;
-    value: string;
-    isInheritable: boolean;
+    position?: number;
+    value?: string;
+    isInheritable?: boolean;
     utcDateModified?: string;
 }
 
@@ -79,9 +79,10 @@ export interface BranchRow {
     branchId?: string;
     noteId: string;
     parentNoteId: string;
-    prefix: string | null;
-    notePosition: number;
-    isExpanded: boolean;
+    prefix?: string | null;
+    notePosition: number | null;
+    isExpanded?: boolean;
+    isDeleted?: boolean;
     utcDateModified?: string;
 }
 
@@ -94,13 +95,19 @@ export type NoteType = ("file" | "image" | "search" | "noteMap" | "launcher" | "
 
 export interface NoteRow {
     noteId: string;
+    deleteId: string;
     title: string;
     type: NoteType;
     mime: string;
     isProtected: boolean;
+    isDeleted: boolean;
     blobId: string;
     dateCreated: string;
     dateModified: string;
     utcDateCreated: string;
     utcDateModified: string;
+}
+
+export interface AttributeRow {
+    
 }
\ No newline at end of file
diff --git a/src/errors/validation_error.ts b/src/errors/validation_error.ts
index 0cabecc8e..8b872bcbe 100644
--- a/src/errors/validation_error.ts
+++ b/src/errors/validation_error.ts
@@ -6,4 +6,4 @@ class ValidationError {
     }
 }
 
-module.exports = ValidationError;
\ No newline at end of file
+export = ValidationError;
\ No newline at end of file
diff --git a/src/etapi/notes.js b/src/etapi/notes.js
index 76318a89d..0d96468d4 100644
--- a/src/etapi/notes.js
+++ b/src/etapi/notes.js
@@ -2,7 +2,7 @@ const becca = require('../becca/becca');
 const utils = require('../services/utils');
 const eu = require('./etapi_utils');
 const mappers = require('./mappers.js');
-const noteService = require('../services/notes.js');
+const noteService = require('../services/notes');
 const TaskContext = require('../services/task_context');
 const v = require('./validators.js');
 const searchService = require('../services/search/services/search.js');
diff --git a/src/routes/api/clipper.js b/src/routes/api/clipper.js
index 1b8bee19b..b5cda8c31 100644
--- a/src/routes/api/clipper.js
+++ b/src/routes/api/clipper.js
@@ -2,7 +2,7 @@
 
 const attributeService = require('../../services/attributes.js');
 const cloneService = require('../../services/cloning.js');
-const noteService = require('../../services/notes.js');
+const noteService = require('../../services/notes');
 const dateNoteService = require('../../services/date_notes.js');
 const dateUtils = require('../../services/date_utils');
 const imageService = require('../../services/image.js');
diff --git a/src/routes/api/files.js b/src/routes/api/files.js
index 5e0c391d6..f368383d5 100644
--- a/src/routes/api/files.js
+++ b/src/routes/api/files.js
@@ -3,7 +3,7 @@
 const protectedSessionService = require('../../services/protected_session');
 const utils = require('../../services/utils');
 const log = require('../../services/log');
-const noteService = require('../../services/notes.js');
+const noteService = require('../../services/notes');
 const tmp = require('tmp');
 const fs = require('fs');
 const { Readable } = require('stream');
diff --git a/src/routes/api/notes.js b/src/routes/api/notes.js
index 7c8ccf773..4f3f89176 100644
--- a/src/routes/api/notes.js
+++ b/src/routes/api/notes.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const noteService = require('../../services/notes.js');
+const noteService = require('../../services/notes');
 const eraseService = require('../../services/erase');
 const treeService = require('../../services/tree.js');
 const sql = require('../../services/sql');
diff --git a/src/routes/api/recent_changes.js b/src/routes/api/recent_changes.js
index 6fea4a105..44e964ecf 100644
--- a/src/routes/api/recent_changes.js
+++ b/src/routes/api/recent_changes.js
@@ -2,7 +2,7 @@
 
 const sql = require('../../services/sql');
 const protectedSessionService = require('../../services/protected_session');
-const noteService = require('../../services/notes.js');
+const noteService = require('../../services/notes');
 const becca = require('../../becca/becca');
 
 function getRecentChanges(req) {
diff --git a/src/routes/api/sender.js b/src/routes/api/sender.js
index 000d1eecb..3c405ecc1 100644
--- a/src/routes/api/sender.js
+++ b/src/routes/api/sender.js
@@ -2,7 +2,7 @@
 
 const imageType = require('image-type');
 const imageService = require('../../services/image.js');
-const noteService = require('../../services/notes.js');
+const noteService = require('../../services/notes');
 const {sanitizeAttributeName} = require('../../services/sanitize_attribute_name');
 const specialNotesService = require('../../services/special_notes.js');
 
diff --git a/src/services/backend_script_api.js b/src/services/backend_script_api.js
index 66408f367..d8687b944 100644
--- a/src/services/backend_script_api.js
+++ b/src/services/backend_script_api.js
@@ -1,5 +1,5 @@
 const log = require('./log');
-const noteService = require('./notes.js');
+const noteService = require('./notes');
 const sql = require('./sql');
 const utils = require('./utils');
 const attributeService = require('./attributes.js');
diff --git a/src/services/date_notes.js b/src/services/date_notes.js
index 5d74b2f47..628ed886f 100644
--- a/src/services/date_notes.js
+++ b/src/services/date_notes.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const noteService = require('./notes.js');
+const noteService = require('./notes');
 const attributeService = require('./attributes.js');
 const dateUtils = require('./date_utils');
 const sql = require('./sql');
diff --git a/src/services/date_utils.ts b/src/services/date_utils.ts
index 31c58c2e4..82347504c 100644
--- a/src/services/date_utils.ts
+++ b/src/services/date_utils.ts
@@ -65,7 +65,7 @@ function getDateTimeForFile() {
     return new Date().toISOString().substr(0, 19).replace(/:/g, '');
 }
 
-function validateLocalDateTime(str: string) {
+function validateLocalDateTime(str: string | null | undefined) {
     if (!str) {
         return;
     }
@@ -80,7 +80,7 @@ function validateLocalDateTime(str: string) {
     }
 }
 
-function validateUtcDateTime(str: string) {
+function validateUtcDateTime(str?: string) {
     if (!str) {
         return;
     }
diff --git a/src/services/entity_changes.ts b/src/services/entity_changes.ts
index bc75432b0..91f84f834 100644
--- a/src/services/entity_changes.ts
+++ b/src/services/entity_changes.ts
@@ -45,7 +45,7 @@ function putEntityChange(origEntityChange: EntityChange) {
     cls.putEntityChange(ec);
 }
 
-function putNoteReorderingEntityChange(parentNoteId: string, componentId: string) {
+function putNoteReorderingEntityChange(parentNoteId: string, componentId?: string) {
     putEntityChange({
         entityName: "note_reordering",
         entityId: parentNoteId,
diff --git a/src/services/handlers.js b/src/services/handlers.js
index 1a9c8e353..a24e28dd6 100644
--- a/src/services/handlers.js
+++ b/src/services/handlers.js
@@ -1,10 +1,10 @@
 const eventService = require('./events');
 const scriptService = require('./script.js');
 const treeService = require('./tree.js');
-const noteService = require('./notes.js');
+const noteService = require('./notes');
 const becca = require('../becca/becca');
 const BAttribute = require('../becca/entities/battribute');
-const hiddenSubtreeService = require('./hidden_subtree.js');
+const hiddenSubtreeService = require('./hidden_subtree');
 const oneTimeTimer = require('./one_time_timer.js');
 
 function runAttachedRelations(note, relationName, originEntity) {
diff --git a/src/services/hidden_subtree.js b/src/services/hidden_subtree.ts
similarity index 93%
rename from src/services/hidden_subtree.js
rename to src/services/hidden_subtree.ts
index a2f6ec7bb..5478aed1c 100644
--- a/src/services/hidden_subtree.js
+++ b/src/services/hidden_subtree.ts
@@ -1,8 +1,10 @@
-const becca = require('../becca/becca');
-const noteService = require('./notes.js');
-const BAttribute = require('../becca/entities/battribute');
-const log = require('./log');
-const migrationService = require('./migration');
+import BAttribute = require("../becca/entities/battribute");
+import { AttributeType, NoteType } from "../becca/entities/rows";
+
+import becca = require('../becca/becca');
+import noteService = require('./notes');
+import log = require('./log');
+import migrationService = require('./migration');
 
 const LBTPL_ROOT = "_lbTplRoot";
 const LBTPL_BASE = "_lbTplBase";
@@ -13,13 +15,36 @@ const LBTPL_BUILTIN_WIDGET = "_lbTplBuiltinWidget";
 const LBTPL_SPACER = "_lbTplSpacer";
 const LBTPL_CUSTOM_WIDGET = "_lbTplCustomWidget";
 
+interface Attribute {
+    type: AttributeType;
+    name: string;
+    isInheritable?: boolean;
+    value?: string
+}
+
+interface Item {
+    notePosition?: number;
+    id: string;
+    title: string;
+    type: NoteType;
+    icon?: string;
+    attributes?: Attribute[];
+    children?: Item[];
+    isExpanded?: boolean;
+    baseSize?: string;
+    growthFactor?: string;
+    targetNoteId?: "_backendLog" | "_globalNoteMap";
+    builtinWidget?: "bookmarks" | "spacer" | "backInHistoryButton" | "forwardInHistoryButton" | "syncStatus" | "protectedSession" | "todayInJournal" | "calendar";
+    command?: "jumpToNote" | "searchNotes" | "createNoteIntoInbox" | "showRecentChanges";
+}
+
 /*
  * Hidden subtree is generated as a "predictable structure" which means that it avoids generating random IDs to always
  * produce the same structure. This is needed because it is run on multiple instances in the sync cluster which might produce
  * duplicate subtrees. This way, all instances will generate the same structure with the same IDs.
  */
 
-const HIDDEN_SUBTREE_DEFINITION = {
+const HIDDEN_SUBTREE_DEFINITION: Item = {
     id: '_hidden',
     title: 'Hidden Notes',
     type: 'doc',
@@ -244,7 +269,7 @@ function checkHiddenSubtree(force = false) {
     checkHiddenSubtreeRecursively('root', HIDDEN_SUBTREE_DEFINITION);
 }
 
-function checkHiddenSubtreeRecursively(parentNoteId, item) {
+function checkHiddenSubtreeRecursively(parentNoteId: string, item: Item) {
     if (!item.id || !item.type || !item.title) {
         throw new Error(`Item does not contain mandatory properties: ${JSON.stringify(item)}`);
     }
@@ -337,7 +362,7 @@ function checkHiddenSubtreeRecursively(parentNoteId, item) {
     }
 }
 
-module.exports = {
+export = {
     checkHiddenSubtree,
     LBTPL_ROOT,
     LBTPL_BASE,
diff --git a/src/services/html_sanitizer.ts b/src/services/html_sanitizer.ts
index 6e7d8b537..8e82edd3c 100644
--- a/src/services/html_sanitizer.ts
+++ b/src/services/html_sanitizer.ts
@@ -47,7 +47,7 @@ function sanitize(dirtyHtml: string) {
     });
 }
 
-module.exports = {
+export = {
     sanitize,
     sanitizeUrl: (url: string) => {
         return sanitizeUrl.sanitizeUrl(url).trim();
diff --git a/src/services/image.js b/src/services/image.js
index 8d7aec5c8..26c2fbdd3 100644
--- a/src/services/image.js
+++ b/src/services/image.js
@@ -3,7 +3,7 @@
 const becca = require('../becca/becca');
 const log = require('./log');
 const protectedSessionService = require('./protected_session');
-const noteService = require('./notes.js');
+const noteService = require('./notes');
 const optionService = require('./options');
 const sql = require('./sql');
 const jimp = require('jimp');
@@ -154,7 +154,7 @@ function saveImageToAttachment(noteId, uploadBuffer, originalName, shrinkImageSw
     setTimeout(() => {
         sql.transactional(() => {
             const note = becca.getNoteOrThrow(noteId);
-            const noteService = require('../services/notes.js');
+            const noteService = require('../services/notes');
             noteService.asyncPostProcessContent(note, note.getContent()); // to mark an unused attachment for deletion
         });
     }, 5000);
diff --git a/src/services/import/enex.js b/src/services/import/enex.js
index 80903d9f6..c8379b951 100644
--- a/src/services/import/enex.js
+++ b/src/services/import/enex.js
@@ -4,7 +4,7 @@ const {Throttle} = require('stream-throttle');
 const log = require('../log');
 const utils = require('../utils');
 const sql = require('../sql');
-const noteService = require('../notes.js');
+const noteService = require('../notes');
 const imageService = require('../image.js');
 const protectedSessionService = require('../protected_session');
 const htmlSanitizer = require('../html_sanitizer');
diff --git a/src/services/import/opml.js b/src/services/import/opml.js
index f71b41fbd..2b99dbd85 100644
--- a/src/services/import/opml.js
+++ b/src/services/import/opml.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const noteService = require('../../services/notes.js');
+const noteService = require('../../services/notes');
 const parseString = require('xml2js').parseString;
 const protectedSessionService = require('../protected_session');
 const htmlSanitizer = require('../html_sanitizer');
diff --git a/src/services/import/single.js b/src/services/import/single.js
index b516a50e9..ec7aa735d 100644
--- a/src/services/import/single.js
+++ b/src/services/import/single.js
@@ -1,6 +1,6 @@
 "use strict";
 
-const noteService = require('../../services/notes.js');
+const noteService = require('../../services/notes');
 const imageService = require('../../services/image.js');
 const protectedSessionService = require('../protected_session');
 const markdownService = require('./markdown.js');
diff --git a/src/services/import/zip.js b/src/services/import/zip.js
index db8565037..ee7a828d1 100644
--- a/src/services/import/zip.js
+++ b/src/services/import/zip.js
@@ -3,7 +3,7 @@
 const BAttribute = require('../../becca/entities/battribute');
 const utils = require('../../services/utils');
 const log = require('../../services/log');
-const noteService = require('../../services/notes.js');
+const noteService = require('../../services/notes');
 const attributeService = require('../../services/attributes.js');
 const BBranch = require('../../becca/entities/bbranch');
 const path = require('path');
diff --git a/src/services/notes.js b/src/services/notes.ts
similarity index 81%
rename from src/services/notes.js
rename to src/services/notes.ts
index 3b662e831..c03c96a1e 100644
--- a/src/services/notes.js
+++ b/src/services/notes.ts
@@ -1,52 +1,62 @@
-const sql = require('./sql');
-const optionService = require('./options');
-const dateUtils = require('./date_utils');
-const entityChangesService = require('./entity_changes');
-const eventService = require('./events');
-const cls = require('../services/cls');
-const protectedSessionService = require('../services/protected_session');
-const log = require('../services/log');
-const utils = require('../services/utils');
-const revisionService = require('./revisions');
-const request = require('./request');
-const path = require('path');
-const url = require('url');
-const becca = require('../becca/becca');
-const BBranch = require('../becca/entities/bbranch');
-const BNote = require('../becca/entities/bnote');
-const BAttribute = require('../becca/entities/battribute');
-const BAttachment = require('../becca/entities/battachment');
-const dayjs = require("dayjs");
-const htmlSanitizer = require('./html_sanitizer');
-const ValidationError = require('../errors/validation_error');
-const noteTypesService = require('./note_types');
-const fs = require("fs");
-const ws = require('./ws');
-const html2plaintext = require('html2plaintext')
+import sql = require('./sql');
+import optionService = require('./options');
+import dateUtils = require('./date_utils');
+import entityChangesService = require('./entity_changes');
+import eventService = require('./events');
+import cls = require('../services/cls');
+import protectedSessionService = require('../services/protected_session');
+import log = require('../services/log');
+import utils = require('../services/utils');
+import revisionService = require('./revisions');
+import request = require('./request');
+import path = require('path');
+import url = require('url');
+import becca = require('../becca/becca');
+import BBranch = require('../becca/entities/bbranch');
+import BNote = require('../becca/entities/bnote');
+import BAttribute = require('../becca/entities/battribute');
+import BAttachment = require('../becca/entities/battachment');
+import dayjs = require("dayjs");
+import htmlSanitizer = require('./html_sanitizer');
+import ValidationError = require('../errors/validation_error');
+import noteTypesService = require('./note_types');
+import fs = require("fs");
+import ws = require('./ws');
+import html2plaintext = require('html2plaintext');
+import { AttachmentRow, AttributeRow, BranchRow, NoteRow, NoteType } from '../becca/entities/rows';
+import TaskContext = require('./task_context');
 
-/** @param {BNote} parentNote */
-function getNewNotePosition(parentNote) {
+interface FoundLink {
+    name: "imageLink" | "internalLink" | "includeNoteLink" | "relationMapLink",
+    value: string
+}
+
+interface Attachment {
+    attachmentId?: string;
+    title: string;
+}
+
+function getNewNotePosition(parentNote: BNote) {
     if (parentNote.isLabelTruthy('newNotesOnTop')) {
         const minNotePos = parentNote.getChildBranches()
-            .filter(branch => branch.noteId !== '_hidden') // has "always last" note position
-            .reduce((min, note) => Math.min(min, note.notePosition), 0);
+            .filter(branch => branch?.noteId !== '_hidden') // has "always last" note position
+            .reduce((min, note) => Math.min(min, note?.notePosition || 0), 0);
 
         return minNotePos - 10;
     } else {
         const maxNotePos = parentNote.getChildBranches()
-            .filter(branch => branch.noteId !== '_hidden') // has "always last" note position
-            .reduce((max, note) => Math.max(max, note.notePosition), 0);
+            .filter(branch => branch?.noteId !== '_hidden') // has "always last" note position
+            .reduce((max, note) => Math.max(max, note?.notePosition || 0), 0);
 
         return maxNotePos + 10;
     }
 }
 
-/** @param {BNote} note */
-function triggerNoteTitleChanged(note) {
+function triggerNoteTitleChanged(note: BNote) {
     eventService.emit(eventService.NOTE_TITLE_CHANGED, note);
 }
 
-function deriveMime(type, mime) {
+function deriveMime(type: string, mime?: string) {
     if (!type) {
         throw new Error(`Note type is a required param`);
     }
@@ -58,11 +68,7 @@ function deriveMime(type, mime) {
     return noteTypesService.getDefaultMimeForNoteType(type);
 }
 
-/**
- * @param {BNote} parentNote
- * @param {BNote} childNote
- */
-function copyChildAttributes(parentNote, childNote) {
+function copyChildAttributes(parentNote: BNote, childNote: BNote) {
     for (const attr of parentNote.getAttributes()) {
         if (attr.name.startsWith("child:")) {
             const name = attr.name.substr(6);
@@ -86,8 +92,7 @@ function copyChildAttributes(parentNote, childNote) {
     }
 }
 
-/** @param {BNote} parentNote */
-function getNewNoteTitle(parentNote) {
+function getNewNoteTitle(parentNote: BNote) {
     let title = "new note";
 
     const titleTemplate = parentNote.getLabelValue('titleTemplate');
@@ -101,7 +106,7 @@ function getNewNoteTitle(parentNote) {
             // - parentNote
 
             title = eval(`\`${titleTemplate}\``);
-        } catch (e) {
+        } catch (e: any) {
             log.error(`Title template of note '${parentNote.noteId}' failed with: ${e.message}`);
         }
     }
@@ -114,7 +119,13 @@ function getNewNoteTitle(parentNote) {
     return title;
 }
 
-function getAndValidateParent(params) {
+interface GetValidateParams {
+    parentNoteId: string;
+    type: string;
+    ignoreForbiddenParents?: boolean;
+}
+
+function getAndValidateParent(params: GetValidateParams) {
     const parentNote = becca.notes[params.parentNoteId];
 
     if (!parentNote) {
@@ -141,24 +152,33 @@ function getAndValidateParent(params) {
     return parentNote;
 }
 
-/**
- * Following object properties are mandatory:
- * - {string} parentNoteId
- * - {string} title
- * - {*} content
- * - {string} type - text, code, file, image, search, book, relationMap, canvas, render
- *
- * The following are optional (have defaults)
- * - {string} mime - value is derived from default mimes for type
- * - {boolean} isProtected - default is false
- * - {boolean} isExpanded - default is false
- * - {string} prefix - default is empty string
- * - {int} notePosition - default is the last existing notePosition in a parent + 10
- *
- * @param params
- * @returns {{note: BNote, branch: BBranch}}
- */
-function createNewNote(params) {
+interface NoteParams {
+    /** optionally can force specific noteId */
+    noteId?: string;
+    parentNoteId: string;
+    templateNoteId?: string;
+    title: string;
+    content: string;
+    type: NoteType;
+    /** default value is derived from default mimes for type */
+    mime?: string;
+    /** default is false */
+    isProtected?: boolean;
+    /** default is false */
+    isExpanded?: boolean;
+    /** default is empty string */
+    prefix?: string;
+    /** default is the last existing notePosition in a parent + 10 */
+    notePosition?: number;
+    dateCreated?: string;
+    utcDateCreated?: string;
+    ignoreForbiddenParents?: boolean;
+}
+
+function createNewNote(params: NoteParams): {
+    note: BNote;
+    branch: BBranch;
+} {
     const parentNote = getAndValidateParent(params);
 
     if (params.title === null || params.title === undefined) {
@@ -209,7 +229,7 @@ function createNewNote(params) {
                 noteId: note.noteId,
                 parentNoteId: params.parentNoteId,
                 notePosition: params.notePosition !== undefined ? params.notePosition : getNewNotePosition(parentNote),
-                prefix: params.prefix,
+                prefix: params.prefix || "",
                 isExpanded: !!params.isExpanded
             }).save();
         }
@@ -253,7 +273,7 @@ function createNewNote(params) {
     });
 }
 
-function createNewNoteWithTarget(target, targetBranchId, params) {
+function createNewNoteWithTarget(target: ("into" | "after"), targetBranchId: string, params: NoteParams) {
     if (!params.type) {
         const parentNote = becca.notes[params.parentNoteId];
 
@@ -285,13 +305,7 @@ function createNewNoteWithTarget(target, targetBranchId, params) {
     }
 }
 
-/**
- * @param {BNote} note
- * @param {boolean} protect
- * @param {boolean} includingSubTree
- * @param {TaskContext} taskContext
- */
-function protectNoteRecursively(note, protect, includingSubTree, taskContext) {
+function protectNoteRecursively(note: BNote, protect: boolean, includingSubTree: boolean, taskContext: TaskContext) {
     protectNote(note, protect);
 
     taskContext.increaseProgressCount();
@@ -303,11 +317,7 @@ function protectNoteRecursively(note, protect, includingSubTree, taskContext) {
     }
 }
 
-/**
- * @param {BNote} note
- * @param {boolean} protect
- */
-function protectNote(note, protect) {
+function protectNote(note: BNote, protect: boolean) {
     if (!protectedSessionService.isProtectedSessionAvailable()) {
         throw new Error(`Cannot (un)protect note '${note.noteId}' with protect flag '${protect}' without active protected session`);
     }
@@ -345,8 +355,8 @@ function protectNote(note, protect) {
     }
 }
 
-function checkImageAttachments(note, content) {
-    const foundAttachmentIds = new Set();
+function checkImageAttachments(note: BNote, content: string) {
+    const foundAttachmentIds = new Set<string>();
     let match;
 
     const imgRegExp = /src="[^"]*api\/attachments\/([a-zA-Z0-9_]+)\/image/g;
@@ -362,7 +372,7 @@ function checkImageAttachments(note, content) {
     const attachments = note.getAttachments();
 
     for (const attachment of attachments) {
-        const attachmentInContent = foundAttachmentIds.has(attachment.attachmentId);
+        const attachmentInContent = attachment.attachmentId && foundAttachmentIds.has(attachment.attachmentId);
 
         if (attachment.utcDateScheduledForErasureSince && attachmentInContent) {
             attachment.utcDateScheduledForErasureSince = null;
@@ -373,7 +383,7 @@ function checkImageAttachments(note, content) {
         }
     }
 
-    const existingAttachmentIds = new Set(attachments.map(att => att.attachmentId));
+    const existingAttachmentIds = new Set<string | undefined>(attachments.map(att => att.attachmentId));
     const unknownAttachmentIds = Array.from(foundAttachmentIds).filter(foundAttId => !existingAttachmentIds.has(foundAttId));
     const unknownAttachments = becca.getAttachments(unknownAttachmentIds);
 
@@ -412,7 +422,7 @@ function checkImageAttachments(note, content) {
     };
 }
 
-function findImageLinks(content, foundLinks) {
+function findImageLinks(content: string, foundLinks: FoundLink[]) {
     const re = /src="[^"]*api\/images\/([a-zA-Z0-9_]+)\//g;
     let match;
 
@@ -428,7 +438,7 @@ function findImageLinks(content, foundLinks) {
     return content.replace(/src="[^"]*\/api\/images\//g, 'src="api/images/');
 }
 
-function findInternalLinks(content, foundLinks) {
+function findInternalLinks(content: string, foundLinks: FoundLink[]) {
     const re = /href="[^"]*#root[a-zA-Z0-9_\/]*\/([a-zA-Z0-9_]+)\/?"/g;
     let match;
 
@@ -443,7 +453,7 @@ function findInternalLinks(content, foundLinks) {
     return content.replace(/href="[^"]*#root/g, 'href="#root');
 }
 
-function findIncludeNoteLinks(content, foundLinks) {
+function findIncludeNoteLinks(content: string, foundLinks: FoundLink[]) {
     const re = /<section class="include-note[^>]+data-note-id="([a-zA-Z0-9_]+)"[^>]*>/g;
     let match;
 
@@ -457,7 +467,7 @@ function findIncludeNoteLinks(content, foundLinks) {
     return content;
 }
 
-function findRelationMapLinks(content, foundLinks) {
+function findRelationMapLinks(content: string, foundLinks: FoundLink[]) {
     const obj = JSON.parse(content);
 
     for (const note of obj.notes) {
@@ -468,9 +478,9 @@ function findRelationMapLinks(content, foundLinks) {
     }
 }
 
-const imageUrlToAttachmentIdMapping = {};
+const imageUrlToAttachmentIdMapping: Record<string, string> = {};
 
-async function downloadImage(noteId, imageUrl) {
+async function downloadImage(noteId: string, imageUrl: string) {
     const unescapedUrl = utils.unescapeHtml(imageUrl);
 
     try {
@@ -493,7 +503,7 @@ async function downloadImage(noteId, imageUrl) {
         }
 
         const parsedUrl = url.parse(unescapedUrl);
-        const title = path.basename(parsedUrl.pathname);
+        const title = path.basename(parsedUrl.pathname || "");
 
         const imageService = require('../services/image.js');
         const attachment = imageService.saveImageToAttachment(noteId, imageBuffer, title, true, true);
@@ -502,21 +512,21 @@ async function downloadImage(noteId, imageUrl) {
 
         log.info(`Download of '${imageUrl}' succeeded and was saved as image attachment '${attachment.attachmentId}' of note '${noteId}'`);
     }
-    catch (e) {
+    catch (e: any) {
         log.error(`Download of '${imageUrl}' for note '${noteId}' failed with error: ${e.message} ${e.stack}`);
     }
 }
 
 /** url => download promise */
-const downloadImagePromises = {};
+const downloadImagePromises: Record<string, Promise<void>> = {};
 
-function replaceUrl(content, url, attachment) {
+function replaceUrl(content: string, url: string, attachment: Attachment) {
     const quotedUrl = utils.quoteRegex(url);
 
     return content.replace(new RegExp(`\\s+src=[\"']${quotedUrl}[\"']`, "ig"), ` src="api/attachments/${attachment.attachmentId}/image/${encodeURIComponent(attachment.title)}"`);
 }
 
-function downloadImages(noteId, content) {
+function downloadImages(noteId: string, content: string) {
     const imageRe = /<img[^>]*?\ssrc=['"]([^'">]+)['"]/ig;
     let imageMatch;
 
@@ -589,6 +599,11 @@ function downloadImages(noteId, content) {
                 const origContent = origNote.getContent();
                 let updatedContent = origContent;
 
+                if (typeof updatedContent !== "string") {
+                    log.error(`Note '${noteId}' has a non-string content, cannot replace image link.`);
+                    return;
+                }
+
                 for (const url in imageUrlToAttachmentIdMapping) {
                     const imageNote = imageNotes.find(note => note.noteId === imageUrlToAttachmentIdMapping[url]);
 
@@ -612,11 +627,7 @@ function downloadImages(noteId, content) {
     return content;
 }
 
-/**
- * @param {BNote} note
- * @param {string} content
- */
-function saveAttachments(note, content) {
+function saveAttachments(note: BNote, content: string) {
     const inlineAttachmentRe = /<a[^>]*?\shref=['"]data:([^;'">]+);base64,([^'">]+)['"][^>]*>(.*?)<\/a>/igm;
     let attachmentMatch;
 
@@ -645,11 +656,7 @@ function saveAttachments(note, content) {
     return content;
 }
 
-/**
- * @param {BNote} note
- * @param {string} content
- */
-function saveLinks(note, content) {
+function saveLinks(note: BNote, content: string) {
     if ((note.type !== 'text' && note.type !== 'relationMap')
         || (note.isProtected && !protectedSessionService.isProtectedSessionAvailable())) {
         return {
@@ -658,7 +665,7 @@ function saveLinks(note, content) {
         };
     }
 
-    const foundLinks = [];
+    const foundLinks: FoundLink[] = [];
     let forceFrontendReload = false;
 
     if (note.type === 'text') {
@@ -716,8 +723,7 @@ function saveLinks(note, content) {
     return { forceFrontendReload, content };
 }
 
-/** @param {BNote} note */
-function saveRevisionIfNeeded(note) {
+function saveRevisionIfNeeded(note: BNote) {
     // files and images are versioned separately
     if (note.type === 'file' || note.type === 'image' || note.isLabelTruthy('disableVersioning')) {
         return;
@@ -738,10 +744,10 @@ function saveRevisionIfNeeded(note) {
     }
 }
 
-function updateNoteData(noteId, content, attachments = []) {
+function updateNoteData(noteId: string, content: string, attachments: BAttachment[] = []) {
     const note = becca.getNote(noteId);
 
-    if (!note.isContentAvailable()) {
+    if (!note || !note.isContentAvailable()) {
         throw new Error(`Note '${noteId}' is not available for change!`);
     }
 
@@ -752,10 +758,13 @@ function updateNoteData(noteId, content, attachments = []) {
     note.setContent(newContent, { forceFrontendReload });
 
     if (attachments?.length > 0) {
-        /** @var {Object<string, BAttachment>} */
         const existingAttachmentsByTitle = utils.toMap(note.getAttachments({includeContentLength: false}), 'title');
 
-        for (const {attachmentId, role, mime, title, content, position} of attachments) {
+        for (const attachment of attachments) {
+            // FIXME: The content property was extracted directly instead of `getContent`. To investigate.
+            const {attachmentId, role, mime, title, position} = attachment;
+            const content = attachment.getContent();
+
             if (attachmentId || !(title in existingAttachmentsByTitle)) {
                 note.saveAttachment({attachmentId, role, mime, title, content, position});
             } else {
@@ -769,12 +778,8 @@ function updateNoteData(noteId, content, attachments = []) {
     }
 }
 
-/**
- * @param {string} noteId
- * @param {TaskContext} taskContext
- */
-function undeleteNote(noteId, taskContext) {
-    const noteRow = sql.getRow("SELECT * FROM notes WHERE noteId = ?", [noteId]);
+function undeleteNote(noteId: string, taskContext: TaskContext) {
+    const noteRow = sql.getRow<NoteRow>("SELECT * FROM notes WHERE noteId = ?", [noteId]);
 
     if (!noteRow.isDeleted) {
         log.error(`Note '${noteId}' is not deleted and thus cannot be undeleted.`);
@@ -793,19 +798,14 @@ function undeleteNote(noteId, taskContext) {
     }
 }
 
-/**
- * @param {string} branchId
- * @param {string} deleteId
- * @param {TaskContext} taskContext
- */
-function undeleteBranch(branchId, deleteId, taskContext) {
-    const branchRow = sql.getRow("SELECT * FROM branches WHERE branchId = ?", [branchId])
+function undeleteBranch(branchId: string, deleteId: string, taskContext: TaskContext) {
+    const branchRow = sql.getRow<BranchRow>("SELECT * FROM branches WHERE branchId = ?", [branchId])
 
     if (!branchRow.isDeleted) {
         return;
     }
 
-    const noteRow = sql.getRow("SELECT * FROM notes WHERE noteId = ?", [branchRow.noteId]);
+    const noteRow = sql.getRow<NoteRow>("SELECT * FROM notes WHERE noteId = ?", [branchRow.noteId]);
 
     if (noteRow.isDeleted && noteRow.deleteId !== deleteId) {
         return;
@@ -818,10 +818,14 @@ function undeleteBranch(branchId, deleteId, taskContext) {
     if (noteRow.isDeleted && noteRow.deleteId === deleteId) {
         // becca entity was already created as skeleton in "new Branch()" above
         const noteEntity = becca.getNote(noteRow.noteId);
+        if (!noteEntity) {
+            throw new Error("Unable to find the just restored branch.");
+        }
+
         noteEntity.updateFromRow(noteRow);
         noteEntity.save();
 
-        const attributeRows = sql.getRows(`
+        const attributeRows = sql.getRows<AttributeRow>(`
                 SELECT * FROM attributes 
                 WHERE isDeleted = 1 
                   AND deleteId = ? 
@@ -830,10 +834,11 @@ function undeleteBranch(branchId, deleteId, taskContext) {
 
         for (const attributeRow of attributeRows) {
             // relation might point to a note which hasn't been undeleted yet and would thus throw up
+            // FIXME: skipValidation is not used.
             new BAttribute(attributeRow).save({skipValidation: true});
         }
 
-        const attachmentRows = sql.getRows(`
+        const attachmentRows = sql.getRows<AttachmentRow>(`
             SELECT * FROM attachments
             WHERE isDeleted = 1
               AND deleteId = ?
@@ -843,7 +848,7 @@ function undeleteBranch(branchId, deleteId, taskContext) {
             new BAttachment(attachmentRow).save();
         }
 
-        const childBranchIds = sql.getColumn(`
+        const childBranchIds = sql.getColumn<string>(`
             SELECT branches.branchId
             FROM branches
             WHERE branches.isDeleted = 1
@@ -859,8 +864,8 @@ function undeleteBranch(branchId, deleteId, taskContext) {
 /**
  * @returns return deleted branchIds of an undeleted parent note
  */
-function getUndeletedParentBranchIds(noteId, deleteId) {
-    return sql.getColumn(`
+function getUndeletedParentBranchIds(noteId: string, deleteId: string) {
+    return sql.getColumn<string>(`
                     SELECT branches.branchId
                     FROM branches
                     JOIN notes AS parentNote ON parentNote.noteId = branches.parentNoteId
@@ -870,7 +875,7 @@ function getUndeletedParentBranchIds(noteId, deleteId) {
                       AND parentNote.isDeleted = 0`, [noteId, deleteId]);
 }
 
-function scanForLinks(note, content) {
+function scanForLinks(note: BNote | null, content: string) {
     if (!note || !['text', 'relationMap'].includes(note.type)) {
         return;
     }
@@ -884,17 +889,15 @@ function scanForLinks(note, content) {
             }
         });
     }
-    catch (e) {
+    catch (e: any) {
         log.error(`Could not scan for links note '${note.noteId}': ${e.message} ${e.stack}`);
     }
 }
 
 /**
- * @param {BNote} note
- * @param {string} content
  * Things which have to be executed after updating content, but asynchronously (separate transaction)
  */
-async function asyncPostProcessContent(note, content) {
+async function asyncPostProcessContent(note: BNote, content: string) {
     if (cls.isMigrationRunning()) {
         // this is rarely needed for migrations, but can cause trouble by e.g. triggering downloads
         return;
@@ -908,7 +911,7 @@ async function asyncPostProcessContent(note, content) {
 }
 
 // all keys should be replaced by the corresponding values
-function replaceByMap(str, mapObj) {
+function replaceByMap(str: string, mapObj: Record<string, string>) {
     if (!mapObj) {
         return str;
     }
@@ -918,7 +921,7 @@ function replaceByMap(str, mapObj) {
     return str.replace(re, matched => mapObj[matched]);
 }
 
-function duplicateSubtree(origNoteId, newParentNoteId) {
+function duplicateSubtree(origNoteId: string, newParentNoteId: string) {
     if (origNoteId === 'root') {
         throw new Error('Duplicating root is not possible');
     }
@@ -931,6 +934,10 @@ function duplicateSubtree(origNoteId, newParentNoteId) {
 
     const noteIdMapping = getNoteIdMapping(origNote);
 
+    if (!origBranch) {
+        throw new Error("Unable to find original branch to duplicate.");
+    }
+
     const res = duplicateSubtreeInner(origNote, origBranch, newParentNoteId, noteIdMapping);
 
     if (!res.note.title.endsWith('(dup)')) {
@@ -942,20 +949,25 @@ function duplicateSubtree(origNoteId, newParentNoteId) {
     return res;
 }
 
-function duplicateSubtreeWithoutRoot(origNoteId, newNoteId) {
+function duplicateSubtreeWithoutRoot(origNoteId: string, newNoteId: string) {
     if (origNoteId === 'root') {
         throw new Error('Duplicating root is not possible');
     }
 
     const origNote = becca.getNote(origNoteId);
+    if (origNote == null) {
+        throw new Error("Unable to find note to duplicate.");
+    }
+    
     const noteIdMapping = getNoteIdMapping(origNote);
-
     for (const childBranch of origNote.getChildBranches()) {
-        duplicateSubtreeInner(childBranch.getNote(), childBranch, newNoteId, noteIdMapping);
+        if (childBranch) {
+            duplicateSubtreeInner(childBranch.getNote(), childBranch, newNoteId, noteIdMapping);
+        }
     }
 }
 
-function duplicateSubtreeInner(origNote, origBranch, newParentNoteId, noteIdMapping) {
+function duplicateSubtreeInner(origNote: BNote, origBranch: BBranch, newParentNoteId: string, noteIdMapping: Record<string, string>) {
     if (origNote.isProtected && !protectedSessionService.isProtectedSessionAvailable()) {
         throw new Error(`Cannot duplicate note '${origNote.noteId}' because it is protected and protected session is not available. Enter protected session and try again.`);
     }
@@ -981,7 +993,7 @@ function duplicateSubtreeInner(origNote, origBranch, newParentNoteId, noteIdMapp
 
         let content = origNote.getContent();
 
-        if (['text', 'relationMap', 'search'].includes(origNote.type)) {
+        if (typeof content === "string" && ['text', 'relationMap', 'search'].includes(origNote.type)) {
             // fix links in the content
             content = replaceByMap(content, noteIdMapping);
         }
@@ -1002,11 +1014,14 @@ function duplicateSubtreeInner(origNote, origBranch, newParentNoteId, noteIdMapp
             }
 
             // the relation targets may not be created yet, the mapping is pre-generated
-            attr.save({skipValidation: true});
+            // FIXME: This used to be `attr.save({skipValidation: true});`, but skipValidation is in beforeSaving.
+            attr.save();
         }
 
         for (const childBranch of origNote.getChildBranches()) {
-            duplicateSubtreeInner(childBranch.getNote(), childBranch, newNote.noteId, noteIdMapping);
+            if (childBranch) {
+                duplicateSubtreeInner(childBranch.getNote(), childBranch, newNote.noteId, noteIdMapping);
+            }
         }
 
         return newNote;
@@ -1031,8 +1046,8 @@ function duplicateSubtreeInner(origNote, origBranch, newParentNoteId, noteIdMapp
     }
 }
 
-function getNoteIdMapping(origNote) {
-    const noteIdMapping = {};
+function getNoteIdMapping(origNote: BNote) {
+    const noteIdMapping: Record<string, string> = {};
 
     // pregenerate new noteIds since we'll need to fix relation references even for not yet created notes
     for (const origNoteId of origNote.getDescendantNoteIds()) {
@@ -1042,7 +1057,7 @@ function getNoteIdMapping(origNote) {
     return noteIdMapping;
 }
 
-module.exports = {
+export = {
     createNewNote,
     createNewNoteWithTarget,
     updateNoteData,
diff --git a/src/services/revisions.ts b/src/services/revisions.ts
index 62ba45cd8..9cd281c13 100644
--- a/src/services/revisions.ts
+++ b/src/services/revisions.ts
@@ -44,6 +44,6 @@ function protectRevisions(note: BNote) {
     }
 }
 
-module.exports = {
+export = {
     protectRevisions
 };
diff --git a/src/services/scheduler.js b/src/services/scheduler.js
index 154671bfa..d4f40cfd7 100644
--- a/src/services/scheduler.js
+++ b/src/services/scheduler.js
@@ -5,7 +5,7 @@ const config = require('./config');
 const log = require('./log');
 const attributeService = require('../services/attributes.js');
 const protectedSessionService = require('../services/protected_session');
-const hiddenSubtreeService = require('./hidden_subtree.js');
+const hiddenSubtreeService = require('./hidden_subtree');
 
 /**
  * @param {BNote} note
diff --git a/src/services/special_notes.js b/src/services/special_notes.js
index fd229a876..749f43325 100644
--- a/src/services/special_notes.js
+++ b/src/services/special_notes.js
@@ -1,13 +1,13 @@
 const attributeService = require('./attributes.js');
 const dateNoteService = require('./date_notes.js');
 const becca = require('../becca/becca');
-const noteService = require('./notes.js');
+const noteService = require('./notes');
 const dateUtils = require('./date_utils');
 const log = require('./log');
 const hoistedNoteService = require('./hoisted_note.js');
 const searchService = require('./search/services/search.js');
 const SearchContext = require('./search/search_context.js');
-const {LBTPL_NOTE_LAUNCHER, LBTPL_CUSTOM_WIDGET, LBTPL_SPACER, LBTPL_SCRIPT} = require('./hidden_subtree.js');
+const {LBTPL_NOTE_LAUNCHER, LBTPL_CUSTOM_WIDGET, LBTPL_SPACER, LBTPL_SCRIPT} = require('./hidden_subtree');
 
 function getInboxNote(date) {
     const workspaceNote = hoistedNoteService.getWorkspaceNote();
diff --git a/src/tools/generate_document.js b/src/tools/generate_document.js
index 9f66e76c9..503fdc6ee 100644
--- a/src/tools/generate_document.js
+++ b/src/tools/generate_document.js
@@ -5,7 +5,7 @@
 
 require('../becca/entity_constructor');
 const sqlInit = require('../services/sql_init');
-const noteService = require('../services/notes.js');
+const noteService = require('../services/notes');
 const attributeService = require('../services/attributes.js');
 const cls = require('../services/cls');
 const cloningService = require('../services/cloning.js');
diff --git a/src/types.d.ts b/src/types.d.ts
new file mode 100644
index 000000000..c4ccea844
--- /dev/null
+++ b/src/types.d.ts
@@ -0,0 +1,14 @@
+/*
+ * This file contains type definitions for libraries that did not have one
+ * in its library or in `@types/*` packages.
+ */
+
+declare module 'unescape' {
+    function unescape(str: string, type?: string): string;
+    export = unescape;
+}
+
+declare module 'html2plaintext' {
+    function html2plaintext(htmlText: string): string;
+    export = html2plaintext;
+}
\ No newline at end of file
diff --git a/src/types/unescape.d.ts b/src/types/unescape.d.ts
deleted file mode 100644
index 465ebd9e9..000000000
--- a/src/types/unescape.d.ts
+++ /dev/null
@@ -1,4 +0,0 @@
-declare module 'unescape' {
-    function unescape(str: string, type?: string): string;
-    export = unescape;
-}
\ No newline at end of file
diff --git a/tsconfig.json b/tsconfig.json
index 9b697666a..bfe575059 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -19,6 +19,6 @@
 		"files": true
 	},
 	"files": [
-		"src/types/unescape.d.ts"
+		"src/types.d.ts"
 	]
   }