Cannot read property 'toString' of null at BootstrapSwitchComponent.ngOnChanges

[SahilParmar123]

Hi i got this error in BootstrapSwitchModule.
My code is :-
maintenanceMode = true or false;
<switch [status]="maintenanceMode" name="maintenanceMode" [(ngModel)]="maintenanceMode" #maintenanceMode="ngModel" [onText]="'ON'" [offText]="'OFF'" [onColor]="'blue'" [offColor]="'gray'" [size]="size" [disabled]="disabled"
(statusChange)="value = !value" ngDefaultControl>

and the error after the submit for the update values.

GeneralSettingComponent.html:555 ERROR TypeError: Cannot read property 'toString' of null
at BootstrapSwitchComponent.ngOnChanges (angular2-bootstrap-switch.umd.js:172)
at checkAndUpdateDirectiveInline (core.js:12365)
at checkAndUpdateNodeInline (core.js:13893)
at checkAndUpdateNode (core.js:13836)
at debugCheckAndUpdateNode (core.js:14729)
at debugCheckDirectivesFn (core.js:14670)
at Object.eval [as updateDirectives] (GeneralSettingComponent.html:555)
at Object.debugUpdateDirectives [as updateDirectives] (core.js:14655)
at checkAndUpdateView (core.js:13802)
at callViewAction (core.js:14153)

please help..
thanks