Remainder/Modulus of string is a number

Question

Why is this even possible?

console.log('13' % 2);

1

I assume JavaScript just converts the string on its own. I would appreciate any info on this behaviour.

Answer 1

As a starting point: http://ecma-international.org/ecma-262/5.1/#sec-11.5

The ToNumber operation is performed on the left argument (which results in the left argument being treated as the number, as explained in http://ecma-international.org/ecma-262/5.1/#sec-9.3.1)