diff --git a/src/Updux.ts b/src/Updux.ts
index 20221a2..3a70c08 100644
--- a/src/Updux.ts
+++ b/src/Updux.ts
@@ -18,6 +18,7 @@ import {
 import { withPayload } from './actions.js';
 import { AggregateActions, Dux, UnionToIntersection } from './types.js';
 import { buildActions } from './buildActions.js';
+import { buildInitial } from './buildInitial.js';
 
 type AggregateState<L> = L;
 
@@ -73,6 +74,8 @@ export default class Updux<
 
     #actions: AggregateActions<ResolveActions<T_LocalActions>, SUBDUXES>;
 
+    #initial: any;
+
     constructor(
         config: Partial<{
             initial: T_LocalState;
@@ -86,6 +89,8 @@ export default class Updux<
         this.#subduxes = config.subduxes ?? ({} as SUBDUXES);
 
         this.#actions = buildActions(this.#localActions, this.#subduxes);
+
+        this.#initial = buildInitial(this.#localInitial, this.#subduxes);
     }
 
     get actions() {
@@ -94,7 +99,7 @@ export default class Updux<
 
     // TODO memoize?
     get initial() {
-        return this.#localInitial;
+        return this.#initial;
     }
 
     createStore(
diff --git a/src/buildInitial.test.ts b/src/buildInitial.test.ts
new file mode 100644
index 0000000..7e8767e
--- /dev/null
+++ b/src/buildInitial.test.ts
@@ -0,0 +1,21 @@
+import { test, expect } from 'vitest';
+import { buildInitial } from './buildInitial.js';
+
+test('basic', () => {
+    expect(
+        buildInitial(
+            { a: 1 },
+            { b: { initial: { c: 2 } }, d: { initial: 'e' } },
+        ),
+    ).toEqual({
+        a: 1,
+        b: { c: 2 },
+        d: 'e',
+    });
+});
+
+test('throw if subduxes and initial is not an object', () => {
+    expect(() => {
+        buildInitial(3, { bar: 'foo' });
+    }).toThrow();
+});
diff --git a/src/buildInitial.ts b/src/buildInitial.ts
new file mode 100644
index 0000000..7e2330e
--- /dev/null
+++ b/src/buildInitial.ts
@@ -0,0 +1,12 @@
+import u from '@yanick/updeep-remeda';
+import * as R from 'remeda';
+
+export function buildInitial(localInitial, subduxes) {
+    if (Object.keys(subduxes).length > 0 && typeof localInitial !== 'object') {
+        throw new Error(
+            "can't have subduxes when the initial value is not an object",
+        );
+    }
+
+    return u(localInitial, R.mapValues(subduxes, R.pathOr(['initial'], {})));
+}
diff --git a/src/initial.test.todo b/src/initial.test.todo
deleted file mode 100644
index 0aa2a85..0000000
--- a/src/initial.test.todo
+++ /dev/null
@@ -1,46 +0,0 @@
-import { test, expect } from 'vitest';
-
-import { Updux } from './Updux.js';
-
-const bar = new Updux({ initial: 123 });
-
-const foo = new Updux({
-    initial: { root: 'abc' },
-    subduxes: {
-        bar,
-    },
-});
-
-test('single dux', () => {
-    const foo = new Updux({
-        initial: { a: 1 },
-    });
-
-    expect(foo.initial).toEqual({ a: 1 });
-});
-
-test('initial value', () => {
-    expect(foo.initial).toEqual({
-        root: 'abc',
-        bar: 123,
-    });
-});
-
-test('splat initial', async () => {
-    const bar = new Updux({
-        initial: { id: 0 },
-    });
-
-    const foo = new Updux({
-        subduxes: { '*': bar },
-    });
-
-    expect(foo.initial).toEqual([]);
-
-    expect(
-        new Updux({
-            initial: 'overriden',
-            subduxes: { '*': bar },
-        }).initial,
-    ).toEqual('overriden');
-});
diff --git a/src/initial.test.ts b/src/initial.test.ts
index 32194e6..74ef278 100644
--- a/src/initial.test.ts
+++ b/src/initial.test.ts
@@ -1,5 +1,15 @@
+import { expectType } from './tutorial.test.js';
 import Updux from './Updux.js';
 
+const bar = new Updux({ initial: 123 });
+
+const foo = new Updux({
+    initial: { root: 'abc' },
+    subduxes: {
+        bar,
+    },
+});
+
 test('default', () => {
     const { initial } = new Updux({});
 
@@ -29,3 +39,60 @@ test('initial to createStore', () => {
         b: 4,
     });
 });
+
+test('single dux', () => {
+    const foo = new Updux({
+        initial: { a: 1 },
+    });
+
+    expect(foo.initial).toEqual({ a: 1 });
+});
+
+// TODO add 'check for no todo eslint rule'
+test.only('initial value', () => {
+    expect(foo.initial).toEqual({
+        root: 'abc',
+        bar: 123,
+    });
+
+    expectType<{
+        root: string;
+        bar: number;
+    }>(foo.initial);
+});
+
+test('no initial', () => {
+    const dux = new Updux({});
+    expectType<{}>(dux.initial);
+    expect(dux.initial).toEqual({});
+});
+
+test('no initial for subdux', () => {
+    const dux = new Updux({
+        subduxes: {
+            bar: new Updux({}),
+            baz: new Updux({ initial: 'potato' }),
+        },
+    });
+    expectType<{ bar: {}; baz: string }>(dux.initial);
+    expect(dux.initial).toEqual({ bar: {}, baz: 'potato' });
+});
+
+test('splat initial', async () => {
+    const bar = new Updux({
+        initial: { id: 0 },
+    });
+
+    const foo = new Updux({
+        subduxes: { '*': bar },
+    });
+
+    expect(foo.initial).toEqual([]);
+
+    expect(
+        new Updux({
+            initial: 'overriden',
+            subduxes: { '*': bar },
+        }).initial,
+    ).toEqual('overriden');
+});
diff --git a/src/tutorial.test.ts b/src/tutorial.test.ts
index 753e746..e763eb4 100644
--- a/src/tutorial.test.ts
+++ b/src/tutorial.test.ts
@@ -1,7 +1,7 @@
 import Updux, { createAction, withPayload } from './index.js';
 import u from '@yanick/updeep-remeda';
 
-const expectType = <T>(value: T) => value;
+export const expectType = <T>(value: T) => value;
 
 test('initial state', () => {
     const initial = {