Simple object pooling solution

ExampleUse.cs

public static class ExampleUse {
  public static void Example(ObjectPoolingSystem pool) {
    pool.Get(ObjectPoolType.SelectFx, fx => {
        fx.transform.position = new Vector3(1, 1, 1);
    });
  }
}

ObjectPoolingSystem.cs

using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Assertions;
using Zenject;

public enum ObjectPoolType
{
    AttackFx,
    SelectFx,
    DeathFx
}

/*
    Object Pooling:
    Something needs to hold the pool(s) 
    Get(poolName, initFn)
        -> find inactive instance
        -> mark as active
        -> call initFn
    Reset(this, poolName) 
        -> mark instance as inactive

*/
public class ObjectPoolingSystem : MonoBehaviour
{
    private Dictionary<ObjectPoolType, List<GameObject>> _pools;
    public GameObject AttackFx;
    public GameObject SelectFx;
    public GameObject DeathFx;
    private DiContainer _ctx;

    [Inject]
    public void Inject(DiContainer ctx) {
        _ctx = ctx;
    }

    // Start is called before the first frame update
    void Start() {
        Assert.IsNotNull(AttackFx);
        Assert.IsNotNull(SelectFx);
        Assert.IsNotNull(DeathFx);

        transform.position = Vector3.zero;

        _pools = new Dictionary<ObjectPoolType, List<GameObject>>();

        InitPool(ObjectPoolType.SelectFx, SelectFx, 6);
        InitPool(ObjectPoolType.AttackFx, AttackFx, 10);
        InitPool(ObjectPoolType.DeathFx, DeathFx, 10);
    }

    private void InitPool(ObjectPoolType t, GameObject prefab, int count) {
        Assert.IsNotNull(prefab);
        Assert.IsTrue(count > 0);

        var lst = new List<GameObject>();
        for (var i = 0; i < count; i++) {
            var go = _ctx.InstantiatePrefab(prefab);
            go.transform.parent = transform;
            go.SetActive(false);
            lst.Add(go);
        }

        _pools.Add(t, lst);
    }

    public void Recycle(GameObject go) {
        Assert.IsNotNull(go);
        go.SetActive(false);
    }

    public GameObject Get(ObjectPoolType t, System.Action<GameObject> initFn = null) {
        var pool = _pools[t];

        if (pool == null) {
            throw new System.Exception("Pool for type " + t + " does not exist, did you initialise it?");
        }

        for (int i = 0; i < pool.Count; i++) {
            if (!pool[i].activeInHierarchy) {
                pool[i].SetActive(true);
                initFn?.Invoke(pool[i]);
                return pool[i];
            }
        }

        Debug.LogError("Object pool empty, cannot find new instance for " + t);
        return null;
    }

    // Update is called once per frame
    void Update() {

    }
}

RecycleOnParticleComplete.cs

using System.Collections;
using System.Collections.Generic;
using TwoPM.View;
using UnityEngine;
using UnityEngine.Assertions;
using Zenject;

namespace GridBased.Fx
{
    public class RecycleOnParticleComplete : MonoBehaviour
    {
        public ParticleSystem ParticleSystem;
        private ObjectPoolingSystem _pool;

        [Inject]
        public void Inject(ObjectPoolingSystem pool) {
            _pool = pool;
        }

        // Start is called before the first frame update
        void Start() {
            Assert.IsNotNull(ParticleSystem);
        }

        // Update is called once per frame
        void Update() {
            if (!ParticleSystem.IsAlive()) {
                _pool.Recycle(gameObject);
            }
        }
    }
}