How to make javascript function can use after dot

Question

I'm doing firebase project these days, and i got a question about something.

var citiesRef = db.collection("cities");
citiesRef.where("state", ">=", "CA").where("population", ">", 100000)

Those where() are stick together after dot and i have no idea. How can i make function or class like that? I don't even know how to search !

I tried to make classes and unnamed functions but it doesn't work.

If i get to know about it, it'll be very useful for me. I really want to know.

Please help please

Your question is very unclear, can you please make your question self explainable by adding some examples instead of describing about it? — Code_Ninja
– Code_Ninja, Commented Dec 11, 2018 at 3:20
i want to make like this function foo() {} foo().foo().foo() — user1436322
– user1436322, Commented Dec 11, 2018 at 3:25
Please refer the link for more details. schier.co/blog/2013/11/14/method-chaining-in-javascript.html — PK'
– PK', Commented Dec 11, 2018 at 3:47

Sid · Accepted Answer · 2018-12-11 03:21:52Z

2

This is something akin to the Builder Pattern. The idea is to return the object after appending a condition.

Example code (language agnostic):

def where(condition){
    self.appendCondition(condition)
    return self  // Important part
}

The return self enables to chain methods on the same object. Each one returns itself with the new condition appended.

answered Dec 11, 2018 at 3:21

Sid

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