Office React Fabric Event Declared But Never Used Demo Code Error - reactjs

Question

When using the Microsoft sample code for the React Office Fabric UI I am getting the error.
TS6133: 'event' is declared but its value is never read.
Code:
https://developer.microsoft.com/en-us/fabric#/controls/web/dropdown
Code Pen: (No Error)
https://codepen.io/pen/?&editable=true
import * as React from 'react';
import { Dropdown, DropdownMenuItemType, IDropdownOption } from 'office-ui-fabric-react/lib/Dropdown';
export interface IDropdownControlledMultiExampleState {
selectedItems: string[];
}
export class DropdownControlledMultiExample extends React.Component<{}, IDropdownControlledMultiExampleState> {
public state: IDropdownControlledMultiExampleState = {
selectedItems: []
};
public render() {
const { selectedItems } = this.state;
return (
<Dropdown
placeholder="Select options"
label="Multi-select controlled example"
selectedKeys={selectedItems}
onChange={this._onChange}
multiSelect
options={[
{ key: 'fruitsHeader', text: 'Fruits', itemType: DropdownMenuItemType.Header },
{ key: 'apple', text: 'Apple' },
{ key: 'banana', text: 'Banana' },
{ key: 'orange', text: 'Orange', disabled: true },
{ key: 'grape', text: 'Grape' },
{ key: 'divider_1', text: '-', itemType: DropdownMenuItemType.Divider },
{ key: 'vegetablesHeader', text: 'Vegetables', itemType: DropdownMenuItemType.Header },
{ key: 'broccoli', text: 'Broccoli' },
{ key: 'carrot', text: 'Carrot' },
{ key: 'lettuce', text: 'Lettuce' }
]}
styles={{ dropdown: { width: 300 } }}
/>
);
}
private _onChange = (event: React.FormEvent<HTMLDivElement>, item: IDropdownOption): void => {
const newSelectedItems = [...this.state.selectedItems];
if (item.selected) {
// add the option if it's checked
newSelectedItems.push(item.key as string);
} else {
// remove the option if it's unchecked
const currIndex = newSelectedItems.indexOf(item.key as string);
if (currIndex > -1) {
newSelectedItems.splice(currIndex, 1);
}
}
this.setState({
selectedItems: newSelectedItems
});
};
}
My use is no different, just implemented outside codepen. I have found the same with all the sample code. What else should be used to utilize the event?

Answer 1

You shouldn't really force yourself to utilize it. An example might be where the _onChange handler is being used for bunch of other forms as well and a need might arise to look into the event object to see where is it coming from etc..
See here: Ignore TS6133: "(import) is declared but never used"?
You need to turn-off the noUnusedLocals option from your tsconfig.json for the error to disappear.