checking a variable value using an OR operator

Question

So, a junior programmer on my team today wrote the following piece of code:

if(status === (\"incomplete\" || \"unknown\"))

Which is obvious

Answer 1

In JavaScript, the || operator returns its first operand if it evaluates to true (i.e. it is not false, null, undefined, "", or 0), and its second operand otherwise.

In the first case, ("incomplete" || "unknown") always evaluates to "incomplete", since it evaluates to true.

The entire condition then becomes:

if (status === "incomplete")

Which explains the behaviour you are observing.