How to interact with the console in NodeJs?

Question

JavaScript

Interested in the interaction of the vanilla node with the console.
For example, make a console calculator on nodejs, without any additional. plugins.
Is it possible to?
Googling found only the implementation through plugins.

Answer 1

process.stdin, google and look deeper

Answer 2

$a=4;
$b=10;
$z= $a*$b;

if ($a && $b > -1) { 
    echo $a-$b;
}
elseif ($a && $b < 0) {
    echo $a * $b;
}    
elseif ($z < -1) {
    echo $a+$b;
}

Answer 3

Parentheses are of course correct, but the "magic" is not in them, the initial problem is that there are extra semicolons.
The parser understood your version as:

$a=4;
$b=10;
$z= $a*$b;
if ($a && $b > -1) {
  echo $a-$b;
} elseif ($a && $b < 0) {};
echo $a * $b; // уже выполнится без условия
elseif ($z < -1) {}; // соответственно уже вообще не относится к предыдущему if'у
echo $a+$b;

Therefore, brackets should be put, with them it is clearer.