JavaScript % (modulo) gives a negative result for negative numbers

Question

According to Google Calculator (-13) % 64 is 51.

According to Javascript (see this JSBin) it is -13.

How do I fix this

Answer 1

The % operator in JavaScript is the remainder operator, not the modulo operator (the main difference being in how negative numbers are treated):

-1 % 8 // -1, not 7