Maximum call stack size exceeded error with merge sort function

p5.js Coding Questions
4

Where is this variable values initialized?:

        values[k] = left[i];

EDIT (March 28, 2021):

Perhaps it is a global variable that is being used within the function, which means that the function is not self-contained. Consequently, we need to have the entire surrounding context of the function available to us in order to reproduce whatever problems you are having.