VoiceOver vs. symbols and units

UIAccessibilityElement+Extensions.swift

extension NSObject {
	// The same can be done for `accessibilityValue` and `accessibilityHint` if needed.
	var smartAccessibilityLabel: String? {
		get { accessibilityLabel }
		set {
			setInBackgroundIfAccessibilityOff(
				\.accessibilityLabel,
				to: newValue?.improvedForReadability
			)
		}
	}

	private func setInBackgroundIfAccessibilityOff(
		_ keyPath: ReferenceWritableKeyPath<NSObject, String?>,
		to value: @autoclosure @escaping () -> String?
	) {
		if UIAccessibility.isVoiceOverRunning
			|| UIAccessibility.isSpeakScreenEnabled
			|| UIAccessibility.isSwitchControlRunning
		{
			self[keyPath: keyPath] = value()
		} else {
			DispatchQueue.global(qos: .background).async { [weak self] in
				let generatedValue = value() // In case it takes time, it's done in background
				DispatchQueue.main.async {
					// Since it's about UI, we do this on the main thread, just to be sure ;)
					self?[keyPath: keyPath] = generatedValue
				}
			}
		}
	}
}

private let number = #"\d(?:[\.,:\s]?\d)*"#

extension String {
	var improvedForReadability: String {
		// List all of the substitutions we want to make
		// Array of tuples of (pattern to match, what to replace it with)
		let substitutions = [
			("/", " per "),
			("(CO²|CO₂)", "CO2"),
			("kWh", "Kilowatt hour"),
			("(n|N)°", "number"),
			("(\(number)) ?/ ?(\(number))", "$1 of $2"),
			("(+/-|+-|±)", "more or less")
		]

		return substitutions.reduce(self) { (string, substitution) in
			let (pattern, replacement) = substitution
			return string.replacing(pattern: pattern, with: replacement)
		}
	}

	func replacing(pattern: String, with replacement: String, options: NSRegularExpression.Options = []) -> String {
		let regex = try! NSRegularExpression(pattern: pattern, options: options)
		return regex.stringByReplacingMatches(
			in: self,
			options: [],
			range: NSRange(location: 0, length: count),
			withTemplate: replacement
		)
	}
}

Can be used like:

label.smartAccessibilityLabel = "2 - 3 bd. • 76 m²" // => "from 2 to 3 bedrooms, 76 square meters"

or:

label.accessibilityLabel = "2 - 3 bd. • 76 m²".improvedForReadability // same result as previous