Access Swift.String character by Int subscript. https://twitter.com/krzyzanowskim/status/1720190374956732789

StringOffsetSubscript.swift

extension StringProtocol {
	
	subscript(_ offset: Int) -> String.Element {
		if offset >= 0 {
			self[index(startIndex, offsetBy: offset)]
		} else {
			self[index(endIndex, offsetBy: offset)]			
		}
	}
	
	subscript(_ offsetRange: Range<Int>) -> SubSequence {
		self[Range<String.Index>(
			uncheckedBounds: (
				lower: index(startIndex, offsetBy: offsetRange.lowerBound),
				upper: index(startIndex, offsetBy: offsetRange.upperBound)
			)
		)]
	}
	
	subscript(_ offsetRange: ClosedRange<Int>) -> SubSequence {
		self[ClosedRange<String.Index>(
			uncheckedBounds: (
				lower: index(startIndex, offsetBy: offsetRange.lowerBound),
				upper: index(startIndex, offsetBy: offsetRange.upperBound)
			)
		)]
	}
}

let text = "abc🫣def"
print(text[4]) // d
print(text[-1]) // f

print(text[0..<4]) // abc🫣
print(text[0...4]) // abc🫣d