Answers for "how to check object key exists or not"

Abap ActionScript Assembly BASIC C C# C++ Clojure Cobol CSS Dart Delphi Elixir Erlang F# Fortran Go Groovy Haskell Html Java Javascript Julia Kotlin Lisp Lua Matlab Objective-C Pascal Perl PHP Prolog Python R Ruby Rust Scala Scheme Shell/Bash SQL Swift TypeScript VBA Whatever