class {
    onInput(input) {
        this.state = { first: true, second: false }
    }
    toggleValue(e) {
        this.state[ e.target.value ] = e.target.checked
    }
}

<div id="the-component">
    <input type="checkbox" name="opts[]" value="first" checked=state.first
        on-change('toggleValue') key="first"/>
    First Checkbox
    <br/>
    <input type="checkbox" name="opts[]" value="second" checked=state.second
        on-change('toggleValue') key="second"/>
    Second Checkbox
</div>