refactors onChange calls

src/components/AddDialog/AddDialog.js

 import React from "react";
 import PropTypes from "prop-types";
 import {Button, TextField,  Dialog, DialogActions,  DialogContent, DialogTitle, Grid } from '@material-ui/core/';
- 
+
 const AddDialog = ({ name, quantity, isOpen, handleClose, handleCancel, handleAdd, updateName, updateQuantity }) => (
   <Dialog
     open={isOpen}
@@ -19,7 +19,7 @@ const AddDialog = ({ name, quantity, isOpen, handleClose, handleCancel, handleAd
               id="name"
               label="Name"
               type="string"
-              onChange={updateName}
+              onChange={(event) => updateName(event.target.value)}
             />
           </Grid>
           <Grid item>
@@ -28,7 +28,8 @@ const AddDialog = ({ name, quantity, isOpen, handleClose, handleCancel, handleAd
               id="quantity"
               label="Quantity"
               type="number"
-              onChange={updateQuantity}
+              value={quantity}
+              onChange={(event) => updateQuantity(event.target.value)}
             />
           </Grid>
         </Grid>
@@ -52,6 +53,6 @@ AddDialog.propTypes = {
   handleClose: PropTypes.func.isRequired, 
   handleCancel: PropTypes.func.isRequired, 
   handleAdd: PropTypes.func.isRequired
-};
+}
 
 export default AddDialog
\ No newline at end of file

src/container/AddDialogContainer/AddDialogContainer.js

@@ -43,8 +43,8 @@ const mapDispatchToProps = (dispatch) => ({
   handleClose: () => dispatch(closeAddDialog()), 
   handleCancel: () => dispatch(closeAddDialog()), 
   handleAdd: (name, quantity) => handleAdd(name, quantity, dispatch),
-  updateName: event => dispatch(updateAddDialogName(event.target.value)),
-  updateQuantity: event => dispatch(updateAddDialogQuantity(Number(event.target.value)))
+  updateName: newName => dispatch(updateAddDialogName(newName)),
+  updateQuantity: newQuantity => dispatch(updateAddDialogQuantity(Number(newQuantity)))
 })
 
 export default connect(