ConstraintDSL.swift

import UIKit

class ConstraintDSL {
  private let view: UIView
  private var chain: [NSLayoutConstraint] = []

  init(_ view: UIView) {
    self.view = view
  }

  func centeredX(to parentView: UIView) -> Self {
    let constraint = view.centerXAnchor.constraint(equalTo: parentView.centerXAnchor)
    chain.append(constraint)
    return self
  }

  func centeredY(to parentView: UIView) -> Self {
    let constraint = view.centerYAnchor.constraint(equalTo: parentView.centerYAnchor)
    chain.append(constraint)
    return self
  }

  func maxWidth(_ constant: CGFloat) -> Self {
    let constraint = view.widthAnchor.constraint(lessThanOrEqualToConstant: constant)
    chain.append(constraint)
    return self
  }

  func minWidth(_ constant: CGFloat) -> Self {
    let constraint = view.widthAnchor.constraint(greaterThanOrEqualToConstant: constant)
    chain.append(constraint)
    return self
  }

  func minPaddingX(_ constant: CGFloat, from parentView: UIView) -> Self {
    let constraintL = view.leadingAnchor.constraint(greaterThanOrEqualTo: parentView.leadingAnchor, constant: constant)
    chain.append(constraintL)
    let constraintR = view.trailingAnchor.constraint(lessThanOrEqualTo: parentView.trailingAnchor, constant: -constant)
    chain.append(constraintR)
    return self
  }

  // ... etc

  func activate() {
    NSLayoutConstraint.activate(chain)
  }
}

ViewController.swift

class Controller: UIViewController {
  override func viewDidLoad() {
    super.viewDidLoad()

    let button = UIButton()
    // ... configuration

    ConstraintDSL(button)
      .centeredX(to: view)
      .centeredY(to: view)
      .minWidth(200)
      .maxWidth(400)
      .minPaddingX(16, from: view)
      .activate()
  }
}