Unity Better Keyboard Listener

PlayerInputModule.cs

// Created by h1ddengames
// Attributes being used within this class require:
// https://github.com/dbrizov/NaughtyAttributes

using System.Collections.Generic;
using UnityEngine;
using NaughtyAttributes;
using UnityEngine.Events;

namespace h1ddengames {
    public class PlayerInputModule : Singleton<PlayerInputModule> {
        #region Exposed Fields
        [NaughtyAttributes.ReorderableList, SerializeField] private List<InputLibrary> inputLibrary = new List<InputLibrary>();
        #endregion

        #region Private Fields
        #endregion

        #region Getters/Setters/Constructors
        public List<InputLibrary> InputLibrary { get => inputLibrary; set => inputLibrary = value; }
        #endregion

        #region My Methods
        #endregion

        #region Unity Methods
        void OnEnable() {

        }

        void Start() {

        }

        void Update() {
            // Go through every element in inputLibrary and check for keypress.
            foreach(var item in InputLibrary) {

                // Checking if a key has been pressed once.
                if(Input.GetKeyDown(item.Key)) {
                    item.SinglePressActions?.Invoke();

                    // Checking if a key has been double pressed within a given timeframe.
                    if((Time.time - item.LastTapTime) < item.DoubleTapThreshold) {
                        item.DoublePressActions?.Invoke();
                    }

                    item.LastTapTime = Time.time;
                }

                // Checking if a key is being held down.
                if(Input.GetKey(item.Key)) {
                    item.Timer += Time.deltaTime;

                    if(item.Timer > item.HoldThreshold) {
                        item.HoldActions?.Invoke();
                        item.Timer = 0;
                    }
                }

                // Reset hold timer if the key is unpressed.
                if(Input.GetKeyUp(item.Key)) {
                    item.Timer = 0;
                }
            }
        }

        void OnDisable() {

        }
        #endregion

        #region Helper Methods
        #endregion
    }

    [System.Serializable]
    public class InputLibrary {
        #region Configuration
        [BoxedHeader("Configuration"),
        Tooltip("The key that is being listened for."),
        SerializeField]
        private KeyCode key;

        [Tooltip("The length of time required for the key to be held down until the hold event fires."),
        SerializeField]
        private float holdThreshold = 0.5f;

        [Tooltip("The length of time between two single presses. " +
            "If less than this value then it's a double press. " +
            "If greater than this value it is a single press."),
        SerializeField]
        private float doubleTapThreshold = 0.3f;

        [Tooltip("The actions to be performed on single press of this button."),
        Space(10),
        SerializeField]
        private UnityEvent singlePressActions;

        [Tooltip("The actions to be performed on double press of this button."),
        SerializeField]
        private UnityEvent doublePressActions;

        [Tooltip("The actions to be performed on holding of this button."),
        SerializeField]
        private UnityEvent holdActions;
        #endregion

        #region Quick Information
        [BoxedHeader("Quick Information"), Space(10)]
        [BoxGroup("Quick Information"), SerializeField] private float timer = 0f;
        [BoxGroup("Quick Information"), SerializeField] private float lastTapTime = 0f;
        #endregion

        #region Getters/Setters/Constructors
        public InputLibrary(KeyCode key, float holdThreshold, float doubleTapThreshold) {
            this.key = key;
            this.holdThreshold = holdThreshold;
            this.doubleTapThreshold = doubleTapThreshold;
        }

        public KeyCode Key { get => key; set => key = value; }
        public float Timer { get => timer; set => timer = value; }
        public float LastTapTime { get => lastTapTime; set => lastTapTime = value; }
        public float HoldThreshold { get => holdThreshold; set => holdThreshold = value; }
        public float DoubleTapThreshold { get => doubleTapThreshold; set => doubleTapThreshold = value; }
        public UnityEvent SinglePressActions { get => singlePressActions; set => singlePressActions = value; }
        public UnityEvent DoublePressActions { get => doublePressActions; set => doublePressActions = value; }
        public UnityEvent HoldActions { get => holdActions; set => holdActions = value; }
        #endregion
    }
}

Singleton.cs

using UnityEngine;

public abstract class Singleton<T> : MonoBehaviour where T : Component {
    #region Fields
    private static T instance;
    #endregion

    #region Properties
    public static T Instance {
        get {
            if(instance == null) {
                instance = FindObjectOfType<T>();
                if(instance == null) {
                    GameObject obj = new GameObject();
                    obj.name = typeof(T).Name;
                    instance = obj.AddComponent<T>();
                }
            }
            return instance;
        }
    }
    #endregion

    #region Methods
    /// <summary>
    /// Use this for initialization.
    /// </summary>
    protected virtual void Awake() {
        if(instance == null) {
            instance = this as T;
            DontDestroyOnLoad(gameObject);
        } else {
            Destroy(gameObject);
        }
    }
    #endregion
}