index.jsx

export const UserEdit = (props) => (
    <Edit title="Edit User" {...props}>
        <SimpleForm>
            <DisabledInput source="_id" />
            <TextInput source="username" />
            <TextInput source="staffNumber" />

        </SimpleForm>
    </Edit>
);

// is the same as 

export const UserEdit = (props) => {
  console.log(props)
   return (
      <Edit title="Edit User" {...props}>
          <SimpleForm>
              <DisabledInput source="_id" />
              <TextInput source="username" />
              <TextInput source="staffNumber" />

          </SimpleForm>
      </Edit>
  );
}