diff --git a/src/logging/BaseLogger.ts b/src/logging/BaseLogger.ts
index 311af22d..7117f9d9 100644
--- a/src/logging/BaseLogger.ts
+++ b/src/logging/BaseLogger.ts
@@ -21,6 +21,10 @@ import {Platform} from "../platform/web/Platform.js";
 
 // todo: move this to LogItem?
 type LabelOrValues = string | {l: string; [key: string]: unknown};
+type LogCallback = (item: LogItem) => Promise<unknown> | undefined;
+// todo: this should be an enum
+type LogLevel = number | null;
+type FilterCreator = ((filter: LogFilter, item: LogItem) => LogFilter) | null;
 
 export abstract class BaseLogger {
     protected _openItems: Set<LogItem> = new Set();
@@ -37,7 +41,7 @@ export abstract class BaseLogger {
     }
 
     /** if item is a log item, wrap the callback in a child of it, otherwise start a new root log item. */
-    wrapOrRun(item, labelOrValues: LabelOrValues, callback, logLevel = null, filterCreator = null) {
+    wrapOrRun(item: LogItem, labelOrValues: LabelOrValues, callback: LogCallback, logLevel: LogLevel = null, filterCreator: FilterCreator = null) {
         if (item) {
             return item.wrap(labelOrValues, callback, logLevel, filterCreator);
         } else {
@@ -50,27 +54,27 @@ export abstract class BaseLogger {
     Useful to pair with LogItem.refDetached.
 
     @return {LogItem} the log item added, useful to pass to LogItem.refDetached */
-    runDetached(labelOrValues: LabelOrValues, callback, logLevel = null, filterCreator = null) {
+    runDetached(labelOrValues: LabelOrValues, callback: LogCallback, logLevel: LogLevel = null, filterCreator: FilterCreator = null) {
         if (logLevel === null) {
             logLevel = LogLevel.Info;
         }
         const item = new LogItem(labelOrValues, logLevel, null, this);
-        this._run(item, callback, logLevel, filterCreator, false /* don't throw, nobody is awaiting */);
+        this._run(item, callback, logLevel!, filterCreator, false /* don't throw, nobody is awaiting */);
         return item;
     }
 
     /** run a callback wrapped in a log operation.
     Errors and duration are transparently logged, also for async operations.
     Whatever the callback returns is returned here. */
-    run(labelOrValues: LabelOrValues, callback, logLevel = null, filterCreator = null) {
+    run(labelOrValues: LabelOrValues, callback: LogCallback, logLevel: LogLevel = null, filterCreator: FilterCreator = null) {
         if (logLevel === null) {
             logLevel = LogLevel.Info;
         }
         const item = new LogItem(labelOrValues, logLevel, null, this);
-        return this._run(item, callback, logLevel, filterCreator, true);
+        return this._run(item, callback, logLevel!, filterCreator, true);
     }
 
-    _run(item, callback, logLevel, filterCreator, shouldThrow) {
+    _run(item: LogItem, callback: LogCallback, logLevel: number, filterCreator: FilterCreator, shouldThrow: boolean) {
         this._openItems.add(item);
 
         const finishItem = () => {