How can i do optional function

i need to do optional function.
How can i do like this:

  console.log(db.(x==true ? input(...) : ["no function"]).query(...));
// if x is true console.log(db.input(...).query(...));
// if x is false console.log(db.query(...));

>Solution :

You don’t need to compare x with true:

console.log((x ? db.input(...) : db).query(...));

You want to call query either on db or on db.input(...) depending on x.

Example:

const db = { input() { return { query() { return 'db.input(...).query(...)'; } } }, query() { return 'db.query(...)'; } };

console.log((true ? db.input() : db).query());
console.log((false ? db.input() : db).query());