CocoaBinding in code

CocoaBindingViewController.swift

import Cocoa

class ViewController: NSViewController {
    let model = NSMutableDictionary()
    private(set) lazy var controller: NSObjectController = .init(content: model)
    let textView1 = NSTextView()
    let textView2 = NSTextView()

    override func viewDidLoad() {
        super.viewDidLoad()

        let views: [String: NSView] = ["tv1": textView1, "tv2": textView2]
        views.values.forEach {
            $0.translatesAutoresizingMaskIntoConstraints = false
            view.addSubview($0)
        }
        view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-[tv1]-[tv2(==tv1)]-|", options: [], metrics: nil, views: views))
        view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-[tv1]-|", options: [], metrics: nil, views: views))
        view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-[tv2]-|", options: [], metrics: nil, views: views))

        // Cocoa Binding
        textView1.bind(.attributedString, to: controller, withKeyPath: "content.bodyText", options: [.continuouslyUpdatesValue: true])
        textView2.bind(.attributedString, to: controller, withKeyPath: "content.bodyText", options: [.continuouslyUpdatesValue: true])

        model["bodyText"] = "initial text"
    }
}