diff --git a/js/src/modals/SMSVerification/GatherData/gatherData.js b/js/src/modals/SMSVerification/GatherData/gatherData.js
index fa24e04e5..f4036a3bc 100644
--- a/js/src/modals/SMSVerification/GatherData/gatherData.js
+++ b/js/src/modals/SMSVerification/GatherData/gatherData.js
@@ -15,6 +15,7 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 import React, { Component, PropTypes } from 'react';
+import nullable from '../../../util/nullable-proptype';
 import BigNumber from 'bignumber.js';
 import { Checkbox } from 'material-ui';
 import InfoIcon from 'material-ui/svg-icons/action/info-outline';
@@ -27,8 +28,6 @@ import { Form, Input } from '../../../ui';
 import terms from '../terms-of-service';
 import styles from './gatherData.css';
 
-const nullable = (type) => PropTypes.oneOfType([ PropTypes.oneOf([ null ]), type ]);
-
 export default class GatherData extends Component {
   static propTypes = {
     fee: React.PropTypes.instanceOf(BigNumber),
diff --git a/js/src/modals/SMSVerification/SendConfirmation/sendConfirmation.js b/js/src/modals/SMSVerification/SendConfirmation/sendConfirmation.js
index b6d4f3dca..a3c8e3e18 100644
--- a/js/src/modals/SMSVerification/SendConfirmation/sendConfirmation.js
+++ b/js/src/modals/SMSVerification/SendConfirmation/sendConfirmation.js
@@ -15,6 +15,7 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 import React, { Component, PropTypes } from 'react';
+import nullable from '../../../util/nullable-proptype';
 
 import TxHash from '../../../ui/TxHash';
 import {
@@ -23,9 +24,6 @@ import {
 
 import styles from './sendConfirmation.css';
 
-// TODO: move this to a better place
-const nullable = (type) => PropTypes.oneOfType([ PropTypes.oneOf([ null ]), type ]);
-
 export default class SendConfirmation extends Component {
   static propTypes = {
     step: PropTypes.any.isRequired,
diff --git a/js/src/modals/SMSVerification/SendRequest/sendRequest.js b/js/src/modals/SMSVerification/SendRequest/sendRequest.js
index 31190f628..6f9a6077f 100644
--- a/js/src/modals/SMSVerification/SendRequest/sendRequest.js
+++ b/js/src/modals/SMSVerification/SendRequest/sendRequest.js
@@ -15,6 +15,7 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 import React, { Component, PropTypes } from 'react';
+import nullable from '../../../util/nullable-proptype';
 
 import TxHash from '../../../ui/TxHash';
 import {
@@ -23,9 +24,6 @@ import {
 
 import styles from './sendRequest.css';
 
-// TODO: move this to a better place
-const nullable = (type) => PropTypes.oneOfType([ PropTypes.oneOf([ null ]), type ]);
-
 export default class SendRequest extends Component {
   static propTypes = {
     step: PropTypes.any.isRequired,
diff --git a/js/src/util/nullable-proptype.js b/js/src/util/nullable-proptype.js
new file mode 100644
index 000000000..331be6c18
--- /dev/null
+++ b/js/src/util/nullable-proptype.js
@@ -0,0 +1,21 @@
+// Copyright 2015, 2016 Ethcore (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+import { PropTypes } from 'react';
+
+export default function (type) {
+  return PropTypes.oneOfType([ PropTypes.oneOf([ null ]), type ]);
+}
diff --git a/js/src/views/Signer/components/SignRequest/SignRequest.js b/js/src/views/Signer/components/SignRequest/SignRequest.js
index 395bc2c7f..719ddeec9 100644
--- a/js/src/views/Signer/components/SignRequest/SignRequest.js
+++ b/js/src/views/Signer/components/SignRequest/SignRequest.js
@@ -15,6 +15,7 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 import React, { Component, PropTypes } from 'react';
+import nullable from '../../../../util/nullable-proptype';
 
 import Account from '../Account';
 import TransactionPendingForm from '../TransactionPendingForm';
@@ -22,8 +23,6 @@ import TxHashLink from '../TxHashLink';
 
 import styles from './SignRequest.css';
 
-const nullable = (type) => React.PropTypes.oneOfType([ React.PropTypes.oneOf([ null ]), type ]);
-
 export default class SignRequest extends Component {
   static contextTypes = {
     api: PropTypes.object
diff --git a/js/src/views/Signer/components/TransactionFinished/TransactionFinished.js b/js/src/views/Signer/components/TransactionFinished/TransactionFinished.js
index 08ed1f7ed..00d6a057f 100644
--- a/js/src/views/Signer/components/TransactionFinished/TransactionFinished.js
+++ b/js/src/views/Signer/components/TransactionFinished/TransactionFinished.js
@@ -15,6 +15,7 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 import React, { Component, PropTypes } from 'react';
+import nullable from '../../../../util/nullable-proptype';
 
 import CircularProgress from 'material-ui/CircularProgress';
 
@@ -29,8 +30,6 @@ import styles from './TransactionFinished.css';
 import * as tUtil from '../util/transaction';
 import { capitalize } from '../util/util';
 
-const nullable = (type) => React.PropTypes.oneOfType([ React.PropTypes.oneOf([ null ]), type ]);
-
 export default class TransactionFinished extends Component {
   static contextTypes = {
     api: PropTypes.object.isRequired