Index out of range Error when Text is empty before the new text will be added.

I got this Error:
Thread 1: Fatal error: Index out of range
Here:

func limboOfNewCharacter(
        _ char: Character,
        index: Int,
        progress: Float) -> LTCharacterLimbo {
            
            let currentRect = newRects[index] <---- here i got : Thread 1: Fatal error: Index out of range
            var currentFontSize = CGFloat(
                LTEasing.easeOutQuint(progress, 0, Float(font.pointSize))

the textlabel was empty (view did load) before i added new text later.

Start at limboOfNewCharacter, especially the newRects[index] access, and reproduce the case where the label is empty when its text is later changed. Trace how newRects is populated before this function runs. Done means adding text after an initially empty label no longer causes an index-out-of-range crash.