E0383: variable assignment to self is no-op

The following contains a no-op (next = next;):

let next = 0;
if (previous !== null) {
  next = next;
}
switchToPage(next);

To fix this, change the assignment so it's not assigning a variable to itself:

let next = 0;
if (previous !== null) {
  next = previous;
}
switchToPage(next);

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