t is not defined (debounce issue)

[2bro-ncsoft]

() => {
    const [checked, setChecked] = React.useState(false);
    const handleChange = e => { ... };

    return (<div>
      <Switch checked={checked} onChange={handleChange} /> // here
    </div>)
}

I rendered code as above.
I wanted to update checked to true or false but when I typed in t only it says error.
Is there way to give a debounce?