Javascript “tuple” notation: what is its point?

Question

At wtfjs, I found that the following is legal javascript.

\",,,\" == Array((null,\'cool\',false,NaN,4)); // true

The argument (null,\

Answer 1

Try this alert((null,'cool',false,NaN,4)) and then you can see.

demo

The reason is because the comma operator evaluates all the statements and return the last one.

Think of this line: a = 1, b = 2, c = 3; it will run each expression so in essence it will set the variables to what you want and return the last value (in this case 3)