Swift Clamping Example

ClampingPlayground.swift

import Foundation
import UIKit

/// Clamps the given `value` into the range defined by `minValue` and `maxValue`. For example:
///
/// (0.0 ... 5.0).clamp(4.2)    =   4.2
/// (0.0 ... 5.0).clamp(-1.3)   =   0.0
/// (0.0 ... 5.0).clamp(6.4)    =   5.0
///
/// Source: https://stackoverflow.com/a/46799935/584548
public func clamp<T>(_ value: T, minValue: T, maxValue: T) -> T where T : Comparable {
    return min(max(value, minValue), maxValue)
}

struct Bound {
    static let lower: CGFloat = 0.0
    static let upper: CGFloat = 1.0
}

var progress: CGFloat = 0.0 {
    didSet {
        //progress = clamp(progress, minValue: Bound.lower, maxValue: Bound.upper)
        progress = (Bound.lower ... Bound.upper).clamp(progress)
    }
}

progress = 1.2
progress

/// ANOTHER APPROACH ///

extension ClosedRange {
    func clamp(_ value: Bound) -> Bound {
        return lowerBound > value ? self.lowerBound
            : upperBound < value ? self.upperBound
            : value
    }
}