Query<T0>.returnPayloadIfEmpty

Description

Boolean. Indicates if the original payload should be returned when the query is empty.

If set to true, returns the original payload when the query is empty. If set to false, returns an empty array.

using System.Collections.Generic;
using System.Linq;
using UnityEditor;
using UnityEditor.Search;
using UnityEngine;

static class Example_Query_returnPayloadIfEmpty
{
    static List<MyObjectType> s_Data;

    [MenuItem("Examples/Query/returnPayloadIfEmpty")]
    public static void RunExample()
    {
        // Set up the query engine
        var queryEngine = new QueryEngine<MyObjectType>();
        queryEngine.AddFilter("id", myObj => myObj.id);
        queryEngine.SetSearchDataCallback(myObj => new[] { myObj.id.ToString(), myObj.name });

        s_Data = new List<MyObjectType>()
        {
            new MyObjectType { id = 0, name = "Test 1", position = new Vector2(0, 0), active = false },
            new MyObjectType { id = 1, name = "Test 2", position = new Vector2(0, 1), active = true }
        };

        // When setting "returnPayloadIfEmpty" to true, empty queries
        // will return the same data set that was passed as input. Otherwise,
        // it will return an empty set.
        var query = queryEngine.Parse("");
        var filteredData = query.Apply(s_Data).ToList();
        Debug.Assert(filteredData.Count == s_Data.Count, "Filtered data should have the same number of items as the input to the query.");
        for (var i = 0; i < filteredData.Count; ++i)
        {
            Debug.Assert(filteredData[i] == s_Data[i], $"Filtered data at index {i} should be the same as the input.");
        }
    }

    class MyObjectType
    {
        public int id { get; set; }
        public string name { get; set; } = string.Empty;
        public Vector2 position { get; set; } = Vector2.zero;
        public bool active { get; set; }

        public override string ToString()
        {
            return $"({id}, {name}, ({position.x}, {position.y}), {active})";
        }
    }
}