Get post all post titles of a post type in a associative array of post_title => ID pair in WordPress

post_titles_array.php

<?php
// query for your post type
$products =  new WP_Query(
    array (
        'post_type'      => 'product',
        'posts_per_page' => -1
    )
);
// we need the array of posts
$posts_array      = $products->posts;
// create a list with needed information
// the key equals the ID, the value is the post_title
$post_title_array = wp_list_pluck( $posts_array, 'post_title', 'ID' );
// See the output of the array
echo '<pre>'.print_r($post_title_array, 1).'</pre>';