How to denote "undefined" as a predicate?
32989
Is there a symbol to mean 'this is undefined'?
56113
Operator precedence with Javascript Ternary operator
138211
Defining a function using a preceding expression
130415
Negating quantifiers with brackets
93559
use "if" rather than "whether" when the object clause is negative?
61783
Returning an unevaluated expression with values substituted in
14849
Decidability of a predicate.
68074
JavaScript 'in' operator for `undefined` elements in Arrays
24759
How do I use the conditional (ternary) operator?
84421
variable === undefined vs. typeof variable === "undefined"
113905
How can I check whether a variable is defined in JavaScript?
82350
Default value on generic predicate as argument
125415
Why is undefined == undefined but NaN != NaN?
619
Why are these constructs using pre and post-increment undefined behavior?
132062
Reference undefined
71670
Predicates and Quantifiers?
22122
How do you use the ? : (conditional) operator in JavaScript?