Wordpress add custom key and value to wp_query response - php

Question

I can get all the posts using this query. What I want to do is to add custom field key and value so that I will able to pass it along with the post object.
$args = array(
'p' => 996,
'status' => 'publish',
'post_type' => 'ajde_events',
'tax_query' => array(
array(
'taxonomy' => 'event_type',
'field' => 'slug',
'terms' => 'cursed-warriors',
),
),
);
$singlePost = new WP_Query($args);
while ($singlePost->have_posts()) : $singlePost->the_post();
endwhile;
If I query this $singlePost->posts I will have the result below
0: [,…]
0: {ID: 996, post_author: "1", post_date: "2019-11-13 11:15:09", post_date_gmt: "2019-11-13 11:15:09",…}
ID: 996
comment_count: "0"
comment_status: "open"
filter: "raw"
.....etc
I want to add something here
I want to know how I can add some keys there like
project_name: "some project"

Answer 1

Custom Fields can be used for this.
If you are using Gutenberg you will find them under the post's options in the post editor. Click the three dots on the top right, select options, toggle the custom fields on then hit the reload page button. After it loads back up you will see the custom fields metabox at the bottom of the editor.
If you are using classic then the custom fields toggle will be under screen options.
It looks like you have a good grasp of how to handle the data from there. You can use get_post_meta with the postID and the key you add or print all the post meta like you have done above.

Answer 2

What I understand is you want to create a field in your CPT then wants to pass its value in wp loop.
First register a metabox
Here you can do that
/**
* Register meta boxes.
*/
function nap_register_meta_boxes() {
add_meta_box('nap-1', __('NAP Details', 'nap'), 'nap_display_callback', 'nap_location');
add_meta_box('featured-nap-1', __('Featured NAP Location', 'featured-nap'), 'featured_nap_display_callback', 'nap_location');
}
add_action('add_meta_boxes', 'nap_register_meta_boxes');
/**
* Meta box display callback.
*
* #param WP_Post $post Current post object.
*/
function nap_display_callback($post) {
include plugin_dir_path(__FILE__) . '/nap-address-form-fields.php';
}
then add fields to it in nap-address-form-fields.php
<div class="nap_box">
<p class="meta-options nap_field">
<label for="project_name">Project Name</label>
<input id="project_name" value="<?php echo esc_attr(get_post_meta(get_the_ID(), 'project_name', true)); ?>" type="text" name="project_name">
</p>
</div>
Then now on main answer to your question , this is how you can pass it to query
$args = array(
'p' => 996,
'status' => 'publish',
'post_type' => 'ajde_events',
'meta_key' => 'project_name',
'meta_value' => 'some project',
'tax_query' => array(
array(
'taxonomy' => 'event_type',
'field' => 'slug',
'terms' => 'cursed-warriors',
),
),
);

Answer 3

I just found out that since $array->posts is an array of objects you need to do this in order to add new key and value to the result
foreach ($singlePost->posts as $po) {
$po->project_name = "My Project";
}