The optional chaining ‘?.’ is an error-proof way to access nested object properties, even if an intermediate property doesn’t exist. It was recently introduced by ECMA International, Technical Committee 39 – ECMAScript which was authored by Claude Pache, Gabriel Isenberg, Daniel Rosenwasser, Dustin Savery. It works similar to Chaining ‘.’ except that it does not report the error, instead it returns a value which is undefined. It also works with function call when we try to make a call to a method which may not exist.
When we want to check a value of the property which is deep inside a tree-like structure, we often have to perform check whether intermediate nodes exist.
let Value = user.dog && user.dog.name;
The Optional Chaining Operator allows a developer to handle many of those cases without repeating themselves and/or assigning intermediate results in temporary variables:
let Value = user.dog?.name;
obj?.prop obj?.[expr] arr?.[index] func?.(args)
Example: Optional Chaining with Object
Example: Optional Chaining with Function Call