How to store values of checked checkboxes in an array in reactjs

I'm using react-checkbox-group from "https://www.npmjs.com/package/react-checkbox-group". I want to add 4 checkboxes on my Web App, each of them having different values. I then want to store those values in an array. I have my code below for what i'm trying to do, and i'm not sure how to handle the 'onChange' event. Right now the array 'baseballItems' has all items initially, and i want the unchecked ones to disappear but i'm open to changing it so it's empty and the checked boxes are populating the array.

`this.state = { baseballItems: ['bat','baseball', 'shoes', 'cap']}

...

<CheckboxGroup
checkboxDepth={2}
name="baseballItems"
value={this.state.baseballItems}
onChange={(event) => this.setState({ baseballItems: [event.target.isChecked]})}>
<label><Checkbox value="bat"/> bat</label>
<label><Checkbox value="baseball"/> baseball</label>
<label><Checkbox value="shoes"/> shoes</label>
<label><Checkbox value="cap"/> cap</label>
</CheckboxGroup>`