如何检查对象为null，然后检查属性为null，然后检查它们是否为null？

Question

I am trying to check if a variable is null inside an object in single line

 let data = {                        
   friends: userData.social.friends?0: userData.social.friends,
}

in the above line how to check if the userData is null and social is null and then friend is null in a single line? i need to set 0 if friends is not there.

this is in my javascript node js app

Answer 1

is falsy sufficient or do you actually need to compare against null ? you could use this pretty standard notation:

let data = {                        
    friends: userData && userData.social && userData.social.friends || 0
}

Answer 2

As you want to check for null as well as assign the value of friends to your variable, i think it will help you out

 let data = { friends: userData ? (userData.social ? (userData.social.friends ? userData.social.friends : 0) : 0) : 0 } 

I hope this fits your need.