Javascript Optional chaining (?.)

When we access the properties of an object or call a function of a type with . operator

We can chain with ? so that if source is undefined or null, it will not throw an error and break the code.

Accessing object properties

const user ={ name :'Vinodh', city:'Erode' }
console.log(user.coordinates.lat); // We will end up with error

So if it is important to chain with ? so that it will not be error when the source coordinates is undefined or null

console.log(user?.coordinates?.lat); // undefined not error

Accessing nonexistent method

let city = "erode"
city.join(); //city.join is not a function

join is an array method, but when accessing on string will result in an error

This can be rectified with ? operator too

city.join?.()

Accessing index of undefined or null array

let cities
console.log(cities[4]) // cannot read properties of undefined

We can rectify with cities?.[4]