Code Inspection: Comma expression

Reports a comma expression. Such expressions are often a sign of overly clever code, and may lead to subtle bugs. Comma expressions in the initializer or in the update section of for loops are ignored.

In the following example, a potentially confusing one-line comma expression is rewritten using three separate statements:

return a++, b = myObject.someValue;

a++;
b = myObject.someValue;
return b;

For more information, refer to Comma operator (MDN).