diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 9d6eefd5..7ec5b918 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -50,13 +50,36 @@ importers:
       typescript: ^3.9.7
   tools/tupctime:
     dependencies:
+      '@types/better-sqlite3': 5.4.0
+      '@types/debug': 4.1.5
+      '@types/node': 14.0.23
       better-sqlite3: 7.0.1
       debug: 4.1.1
+    devDependencies:
+      typescript: 3.9.7
     specifiers:
+      '@types/better-sqlite3': ^5.4.0
+      '@types/debug': ^4.1.5
+      '@types/node': ^14.0.23
       better-sqlite3: ^7.0.1
       debug: ^4.1.1
+      typescript: ^3.9.7
 lockfileVersion: 5.1
 packages:
+  /@types/better-sqlite3/5.4.0:
+    dependencies:
+      '@types/integer': 1.0.1
+    dev: false
+    resolution:
+      integrity: sha512-nzm7lJ7l3jBmGUbtkL8cdOMhPkN6Pw2IM+b0V7iIKba+YKiLrjkIy7vVLsBIVnd7+lgzBzrHsXZxCaFTcmw5Ow==
+  /@types/debug/4.1.5:
+    dev: false
+    resolution:
+      integrity: sha512-Q1y515GcOdTHgagaVFhHnIFQ38ygs/kmxdNpvpou+raI9UO3YZcHDngBSYKQklcKlvA7iuQlmIKbzvmxcOE9CQ==
+  /@types/integer/1.0.1:
+    dev: false
+    resolution:
+      integrity: sha512-DmZDpSVnsuBrOhtHwE1oKmUJ3qVjHhhNQ7WnZy9/RhH3A24Ar+9o4SoaCWcTzQhalpRDIAMsfdoZLWNJtdBR7A==
   /@types/node/14.0.23:
     dev: false
     resolution:
diff --git a/tools/tupctime/index.js b/tools/tupctime/index.ts
similarity index 82%
rename from tools/tupctime/index.js
rename to tools/tupctime/index.ts
index 6053acd9..a41b734c 100644
--- a/tools/tupctime/index.js
+++ b/tools/tupctime/index.ts
@@ -40,7 +40,7 @@ AND name NOT IN ('^', '$')`);
 const updateQuery = db.prepare(`UPDATE node SET mtime = ? WHERE id = ?`);
 
 function update() {
-    const stack = [{isDir: true, id: 0, path: "."}];
+    const stack : {isDir: boolean, id : number, path: string, ctime?: bigint, name?: string}[] = [{isDir: true, id: 0, path: "."}];
 
     let item;
     while (item = stack.pop()) {
@@ -57,11 +57,16 @@ function update() {
             }
         } else {
             // bigint calculation is necessary to avoid rounding errors/spurious update
+            //
+            // typescript doesn't understand second argument to lstatSync, or
+            // that division can work between a number and bigint, so ignore
+            //
+            // @ts-ignore
             const ctime = fs.lstatSync(item.path, {bigint: true}).ctimeMs / 1000n;
             if (ctime !== item.ctime) {
                 debug(`Updating ${item.path}: ${ctime}, ${item.ctime}`);
                 if (updateQuery.run(ctime, item.id).changes !== 1)
-                    throw new Error(`Couldn't update ${path}`);
+                    throw new Error(`Couldn't update ${item.path}`);
             }
         }
     }
diff --git a/tools/tupctime/package.json b/tools/tupctime/package.json
index 7c16e87e..050d1291 100644
--- a/tools/tupctime/package.json
+++ b/tools/tupctime/package.json
@@ -1,7 +1,17 @@
 {
     "dependencies": {
-        "better-sqlite3":"^7.0.1",
-        "debug":"^4.1.1"
+        "@types/better-sqlite3": "^5.4.0",
+        "@types/debug": "^4.1.5",
+        "@types/node": "^14.0.23",
+        "better-sqlite3": "^7.0.1",
+        "debug": "^4.1.1"
     },
-    "type": "module"
+    "type": "module",
+    "scripts": {
+        "prepare": "tsc"
+    },
+    "devDependencies": {
+        "typescript": "^3.9.7"
+    },
+    "main": "./dist/index.js"
 }
diff --git a/tools/tupctime/tsconfig.json b/tools/tupctime/tsconfig.json
new file mode 100644
index 00000000..e37f4e41
--- /dev/null
+++ b/tools/tupctime/tsconfig.json
@@ -0,0 +1,6 @@
+{
+    "extends": "../../tsconfig-base",
+    "compilerOptions": {
+        "outDir": "dist",
+    }
+}
diff --git a/tsconfig-base.json b/tsconfig-base.json
index 43b6acb4..6683b035 100644
--- a/tsconfig-base.json
+++ b/tsconfig-base.json
@@ -1,8 +1,8 @@
 {
     "compilerOptions": {
         "incremental": true,
-        "target": "es2018",
-        "lib": ["es2018"],
+        "target": "es2020",
+        "lib": ["es2020"],
         "module": "esnext",
         "jsx": "react",
         "strict": true,