Disable a DropDownButton in Angular DropDownButton component

import { Component } from '@angular/core';
import { ItemModel } from '@syncfusion/ej2-angular-splitbuttons';

@Component({
    selector: 'app-root',
    template: `<!-- To render DropDownButton. -->
               <button ejs-dropdownbutton [items]='items' content='Message' iconCss='ddb-icons e-message' disabled='true'></button>`
})

export class AppComponent {
   // Initialize action items.
   public items: ItemModel[] = [
    {
        text: 'Edit'
    },
    {
        text: 'Delete'
    },
    {
        text: 'Mark as Read'
    },
    {
        text: 'Like Message'
    }];

}

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { DropDownButtonModule } from '@syncfusion/ej2-angular-splitbuttons';
import { AppComponent } from './app.component';
import { enableRipple } from '@syncfusion/ej2-base';

enableRipple(true);

/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,
        DropDownButtonModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent]
})
export class AppModule { }

import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { enableProdMode } from '@angular/core';
import { AppModule } from './app.module';

enableProdMode();
platformBrowserDynamic().bootstrapModule(AppModule);

#container {
    visibility: hidden;
}

#loader {
  color: #008cff;
  height: 40px;
  left: 45%;
  position: absolute;
  top: 45%;
  width: 30%;
}

@font-face {
font-family: 'e-db-icons';
src:
url(data:application/x-font-ttf;charset=utf-8;base64,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) format('truetype');
font-weight: normal;
font-style: normal;
}

.ddb-icons {
 font-family: 'e-db-icons' !important;
speak: none;
font-size: 55px;
font-style: normal;
font-weight: normal;
font-variant: normal;
text-transform: none;
line-height: 1;
-webkit-font-smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;
}

.e-message::before {
  content: '\e703';
}

button {
  margin: 25px 5px 20px 20px;
}