DynamicForm, update existing record or creating a new one

[abc80]

I'm trying to use a DynamicForm for both adding and updating records in a SQL DataSource, but I'm having problem with telling it if shall update or save.
If the field marked with primaryKey="true" is filled then it shall make an update and if it is empty then it shall make an add operation.

The DataSource is defined by the XML:

<DataSource ID="Contact" serverType="sql" tableName="contact">
<fields>
<field name="id" type="sequence" title="ID" hidden="false" primaryKey="true"/>
<field name="firstName" type="String" required="false" title="First Name" escapeHTML="true"/>
<field name="lastName" type="String" required="false" title="Last Name" escapeHTML="true"/>
</fields>
</DataSource>

and the JavaScript looks like this:

<isomorphic:loadDS ID="Contact" />
isc.DynamicForm.create({
ID:"ContactForm",
autoDraw:false,
autoFetchData:true,
dataSource: Contact,
wrapItemTitles:false,
height:"auto",
width:"auto" })

isc.Button.create({
ID:"ContactFormNewButton",
title:"New",
click:"ContactForm.editNewRecord()" })

function saveOrUpdate() {
if (ContactForm.getField("id").getValue()==null) {
ContactForm.setSaveOperationType(isc.DSOperationType.ADD);
} else {
ContactForm.setSaveOperationType(isc.DSOperationType.UPDATE);
}
ContactForm.saveData();
}

isc.Button.create({
ID:"ContactFormSaveButton",
title:"Save",
click:"saveOrUpdate()"
})


But when pressing the "Save" button the console says:

Uncaught TypeError: Cannot read property 'UPDATE' of undefined
at saveOrUpdate ((index):78)
at _3.eval [as click] (eval at isc__makeFunction (ISC_Core.js?isc_version=v11.1p_2017-11-02.js:77), <anonymous>:3:8)
at _3.isc_StatefulCanvas_handleActivate [as handleActivate] (ISC_Foundation.js?isc_version=v11.1p_2017-11-02.js:233)
at _3.isc_StatefulCanvas_handleClick [as handleClick] (ISC_Foundation.js?isc_version=v11.1p_2017-11-02.js:234)
at _3.isc_c_EventHandler_bubbleEvent [as bubbleEvent] (ISC_Core.js?isc_version=v11.1p_2017-11-02.js:2042)
at _3.isc_c_EventHandler_handleClick [as handleClick] (ISC_Core.js?isc_version=v11.1p_2017-11-02.js:1898)
at _3.isc_c_EventHandler__handleMouseUp [as $k5] (ISC_Core.js?isc_version=v11.1p_2017-11-02.js:1883)
at _3.isc_c_EventHandler_handleMouseUp [as handleMouseUp] (ISC_Core.js?isc_version=v11.1p_2017-11-02.js:1874)
at _3.isc_c_EventHandler_dispatch [as dispatch] (ISC_Core.js?isc_version=v11.1p_2017-11-02.js:2128)
at HTMLDocument.eval (eval at isc__makeFunction (ISC_Core.js?isc_version=v11.1p_2017-11-02.js:77), <anonymous>:3:123)

Any idea what's wrong?

Browser = Chrome, Version 63.0.3239.132 (Officiell version) (64 bitar)
SmartClient Version: v11.1p_2017-11-02/Pro Development Only (built 2017-11-02)