in packages/transform/src/visit.js [215:231]
function shouldRegenerate(node, state) {
if (node.generator) {
if (node.async) {
// Async generator
return state.opts.asyncGenerators !== false;
} else {
// Plain generator
return state.opts.generators !== false;
}
} else if (node.async) {
// Async function
return state.opts.async !== false;
} else {
// Not a generator or async function.
return false;
}
}