Can you explain this in Javascript? console.log( "1" - - "2");

Question

I came across this in Javascript:
console.log( "1" - - "2"); // output 3

Can someone explain it to me. I can't figure it out.
Thanks in advance.

Answer 1

i figured it out. The first minus sign, makes a subtraction. The second minus sign, makes the string a negative number (-2).

so it is 1 - (-2).

by now it's just math logic. - (negative)and -(negative) makes +(positive), that's why it's a positive 3.

Answer 2

It is called type coercion. This is a phenomenon where JavaScript attempts to convert a given value to a format suitable for the operation to be performed. JavaScript recognizes an arithmetic operation here and so tries to convert "1" to a number (which it does successfully, btw). It then recognizes the first subtraction operator. -"2" is a way to cleverly convert to a number. It is in the form +/-variable. For example, +"6" returns the positive integer 6.

So, -"2" converts "2" to 2 and prepends the negative sign, returning -2.

Thus:

"1"--"2" = 1 - (-2)
= 1 + 2 (minus times minus is plus) = 3