Regular expression for finding a function call

I’m trying to find all calls to a function $t
I tried this expression
/$t([^)]+)/g
but this does not work if I have a ) in the string like so

$t('Name (optional)')

other possible complex values can be

$t('hello' + x)
$t("hello"  + x)
$t(`hello ${x}`)
$t(x)

I assume I need a lookbehind?
Thank you