diff --git a/packages/client-db-chain/src/state/consensys/types.js b/packages/client-db-chain/src/state/consensys/types.js
index b72fe5e9..6269fff9 100644
--- a/packages/client-db-chain/src/state/consensys/types.js
+++ b/packages/client-db-chain/src/state/consensys/types.js
@@ -3,17 +3,11 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-import type BN from 'bn.js';
+import type { IdWithU8a, NoneWithBn } from '../typesShared';
 
-export type ChainDb$State$Consensys$Authority = {
-  get: (id: BN | number) => Uint8Array,
-  set: (id: BN | number, publicKey: Uint8Array) => void
-};
+export type ChainDb$State$Consensys$Authority = IdWithU8a;
 
-export type ChainDb$State$Consensys$AuthorityCount = {
-  get: () => BN,
-  set: (count: BN | number) => void
-};
+export type ChainDb$State$Consensys$AuthorityCount = NoneWithBn;
 
 export type ChainDb$State$Consensys = {
   authority: ChainDb$State$Consensys$Authority,
diff --git a/packages/client-db-chain/src/state/governance/types.js b/packages/client-db-chain/src/state/governance/types.js
index 1c1a290e..95bfe372 100644
--- a/packages/client-db-chain/src/state/governance/types.js
+++ b/packages/client-db-chain/src/state/governance/types.js
@@ -3,12 +3,9 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-import type BN from 'bn.js';
+import type { NoneWithBn } from '../typesShared';
 
-export type ChainDb$State$Governance$ApprovalsRatio = {
-  get: () => BN,
-  set: (ratio: BN | number) => void
-};
+export type ChainDb$State$Governance$ApprovalsRatio = NoneWithBn;
 
 export type ChainDb$State$Governance = {
   approvalsRatio: ChainDb$State$Governance$ApprovalsRatio
diff --git a/packages/client-db-chain/src/state/session/types.js b/packages/client-db-chain/src/state/session/types.js
index 0f7cc24a..bce2b83c 100644
--- a/packages/client-db-chain/src/state/session/types.js
+++ b/packages/client-db-chain/src/state/session/types.js
@@ -3,22 +3,13 @@
 // of the ISC license. See the LICENSE file for details.
 // @flow
 
-import type BN from 'bn.js';
+import type { IdWithU8a, NoneWithBn } from '../typesShared';
 
-export type ChainDb$State$Session$Length = {
-  get: () => BN,
-  set: (length: BN | number) => void
-};
+export type ChainDb$State$Session$Length = NoneWithBn;
 
-export type ChainDb$State$Session$Value = {
-  get: (id: BN | number) => Uint8Array,
-  set: (id: BN | number, publicKey: Uint8Array) => void
-};
+export type ChainDb$State$Session$Value = IdWithU8a;
 
-export type ChainDb$State$Session$ValueCount = {
-  get: () => BN,
-  set: (count: BN | number) => void
-}
+export type ChainDb$State$Session$ValueCount = NoneWithBn;
 
 export type ChainDb$State$Session = {
   length: ChainDb$State$Session$Length,
diff --git a/packages/client-db-chain/src/state/staking/types.js b/packages/client-db-chain/src/state/staking/types.js
index 8d53e045..0f10820e 100644
--- a/packages/client-db-chain/src/state/staking/types.js
+++ b/packages/client-db-chain/src/state/staking/types.js
@@ -4,36 +4,22 @@
 // @flow
 
 import type BN from 'bn.js';
+import type { IdWithU8a, NoneWithBn } from '../typesShared';
 
 export type ChainDb$State$Staking$Balance = {
   get (publicKey: Uint8Array): BN,
   set (publicKey: Uint8Array, value: BN | number): void
 }
 
-export type ChainDb$State$Staking$CurrentEra = {
-  get: () => BN,
-  set: (era: BN | number) => void
-}
+export type ChainDb$State$Staking$CurrentEra = NoneWithBn;
 
-export type ChainDb$State$Staking$Intent = {
-  get: (id: BN | number) => Uint8Array,
-  set: (id: BN | number, publicKey: Uint8Array) => void,
-}
+export type ChainDb$State$Staking$Intent = IdWithU8a;
 
-export type ChainDb$State$Staking$IntentLength = {
-  get: () => BN,
-  set: (length: BN | number) => void
-}
+export type ChainDb$State$Staking$IntentLength = NoneWithBn;
 
-export type ChainDb$State$Staking$SessionsPerEra = {
-  get: () => BN,
-  set: (count: BN | number) => void
-}
+export type ChainDb$State$Staking$SessionsPerEra = NoneWithBn;
 
-export type ChainDb$State$Staking$ValidatorCount = {
-  get: () => BN,
-  set: (count: BN | number) => void
-}
+export type ChainDb$State$Staking$ValidatorCount = NoneWithBn;
 
 export type ChainDb$State$Staking = {
   balance: ChainDb$State$Staking$Balance,
diff --git a/packages/client-db-chain/src/state/system/nonce.js b/packages/client-db-chain/src/state/system/nonce.js
index 93892175..2d341349 100644
--- a/packages/client-db-chain/src/state/system/nonce.js
+++ b/packages/client-db-chain/src/state/system/nonce.js
@@ -13,7 +13,7 @@ module.exports = function nonce (db: WrapDbInterface): ChainDb$State$System$Nonc
   return {
     get: (publicKey: Uint8Array): BN =>
       db.getBn64(NONCE_OF(publicKey)),
-    set: (value: number | BN, publicKey: Uint8Array): void =>
-      db.detBn64(NONCE_OF(publicKey), value)
+    set: (publicKey: Uint8Array, value: number | BN): void =>
+      db.setBn64(NONCE_OF(publicKey), value)
   };
 };
diff --git a/packages/client-db-chain/src/state/system/nonce.spec.js b/packages/client-db-chain/src/state/system/nonce.spec.js
index 7e480089..65dadf0e 100644
--- a/packages/client-db-chain/src/state/system/nonce.spec.js
+++ b/packages/client-db-chain/src/state/system/nonce.spec.js
@@ -12,28 +12,39 @@ describe('nonce', () => {
   let system;
 
   beforeEach(() => {
+    const store = {
+      '0xc7f790aa4fc95a8813b0d5734a8c195b': hexToU8a('0x0100000000000000')
+    };
+
     system = index({
-      get: (key) => {
-        switch (u8aToHex(key)) {
-          case '0xc7f790aa4fc95a8813b0d5734a8c195b':
-            return hexToU8a('0x0100000000000000');
-
-          default:
-            return new Uint8Array([]);
-        }
+      get: (key) => store[u8aToHex(key)] || new Uint8Array([]),
+      set: (key, value) => {
+        store[u8aToHex(key)] = value;
       }
     }).system;
   });
 
-  it('returns nonce', () => {
-    expect(
-      system.nonce.get(keyring.one.publicKey()).toNumber()
-    ).toEqual(1);
+  describe('get', () => {
+    it('returns nonce', () => {
+      expect(
+        system.nonce.get(keyring.one.publicKey()).toNumber()
+      ).toEqual(1);
+    });
+
+    it('returns zero nonces', () => {
+      expect(
+        system.nonce.get(keyring.alice.publicKey()).toNumber()
+      ).toEqual(0);
+    });
   });
 
-  it('returns zero nonces', () => {
-    expect(
-      system.nonce.get(keyring.alice.publicKey()).toNumber()
-    ).toEqual(0);
+  describe('set', () => {
+    it('sets a nonce', () => {
+      system.nonce.set(keyring.alice.publicKey(), 666);
+
+      expect(
+        system.nonce.get(keyring.alice.publicKey()).toNumber()
+      ).toEqual(666);
+    });
   });
 });
diff --git a/packages/client-db-chain/src/state/system/types.js b/packages/client-db-chain/src/state/system/types.js
index 5c413dc9..b8355ea3 100644
--- a/packages/client-db-chain/src/state/system/types.js
+++ b/packages/client-db-chain/src/state/system/types.js
@@ -4,11 +4,9 @@
 // @flow
 
 import type BN from 'bn.js';
+import type { IdWithU8a } from '../typesShared';
 
-export type ChainDb$State$System$BlockHash = {
-  get: (block: BN | number) => Uint8Array,
-  set: (block: BN | number, hash: Uint8Array) => void
-};
+export type ChainDb$State$System$BlockHash = IdWithU8a;
 
 export type ChainDb$State$System$Code = {
   get: () => Uint8Array,
@@ -17,7 +15,7 @@ export type ChainDb$State$System$Code = {
 
 export type ChainDb$State$System$Nonce = {
   get: (publicKey: Uint8Array) => BN,
-  set: (nonce: number | BN, publicKey: Uint8Array) => void
+  set: (publicKey: Uint8Array, nonce: number | BN) => void
 };
 
 export type ChainDb$State$System = {
diff --git a/packages/client-db-chain/src/state/typesShared.js b/packages/client-db-chain/src/state/typesShared.js
new file mode 100644
index 00000000..d41b6722
--- /dev/null
+++ b/packages/client-db-chain/src/state/typesShared.js
@@ -0,0 +1,16 @@
+// Copyright 2017-2018 Jaco Greeff
+// This software may be modified and distributed under the terms
+// of the ISC license. See the LICENSE file for details.
+// @flow
+
+import type BN from 'bn.js';
+
+export type IdWithU8a = {
+  get: (id: BN | number) => Uint8Array,
+  set: (id: BN | number, u8a: Uint8Array) => void
+};
+
+export type NoneWithBn = {
+  get: () => BN,
+  set: (length: BN | number) => void
+}