Querying WordPress serialized ACF meta data using WP_Query

functions.php

add_action( 'rest_api_init', function () {

    // Path to meta query route e.g. localhost:3000/wp-json/reazul/v1/daily_post?for_day=10&for_month=3

    register_rest_route( 'reazul/v1', '/daily_post', array(
            'methods' => 'GET', // API request method
            'callback' => 'get_daily_post', // Call back to process request
            'args' => array( // Arguments passed on to the callback and their validations
                'for_day' => array(
                    'required' => true,
                    'validate_callback' => function($param, $request, $key) {
                        return is_numeric( $param ); // Checking for if the value is a number e.g. 1-31
                    }
                ),
                'for_month' => array(
                    'required' => true,
                    'validate_callback' => function($param, $request, $key) {
                        return is_numeric( $param ); // Checking for if the value is a number e.g. 1-12
                    }
                ),
            )
    ) );
});

// Callback function that returns API contents

function get_daily_devotional( WP_REST_Request $request ) {

    $args = array(
            'numberposts'   => 1,
            'post_type'     => 'post',
            'meta_query'    => array(
                'relation'      => 'AND', // Relationship between two variables passed onto callback
                array(
                    'key'       => 'date', // ACF field key
                    'value'     => "".$request->get_param( 'for_day' )."", // Getting query value from request. Additional Quote is used for turning it to string.
                    'compare'   => 'LIKE',
                ),
                array(
                    'key'       => 'month', // ACF field key
                    'value'     => "".$request->get_param( 'for_month' )."", // Getting query value from request. Additional Quote is used for converting it to string.
                    'compare'   => 'LIKE',
                ),
            )
        );
    $the_query = new WP_Query( $args );
    
    // Regular post loop
    if( $the_query->have_posts() ) {
        $data = array();

        while($the_query->have_posts()) {
            $the_query->the_post();
            
            // Generating custom API contents
            $data['ID'] =  get_the_ID();
            $data['title'] =  get_the_title();
            $data['permalink'] = get_the_permalink();
            $data['excerpt'] = wp_trim_words(get_the_content(), 75);
            $data['content'] =  get_the_content();
        }

        return $data;
    } else {
        return new WP_Error( 'no_post', 'No post to show.', array( 'status' => 404 ) );
    }
}

script.js

jQuery(document).ready(function($) {

    $('form#dailyPost').submit(function(event) {
        event.preventDefault();

        // Getting input from two dropdown
        var month = $('#month').val();
        var day = $('#day').val();
        // Formating human readable date for the selected day and month in current year
        var options = { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' };
        var current = new Date();
        var date = new Date(current.getFullYear(), (month - 1), day).toLocaleDateString("en-US",options);
        
        $.ajax({
            url: '/wp-json/reazul/v1/daily_post',
            dataType: 'json',
            data: {for_day: day, for_month: month},
        })
        .done(function(e) {
            $('.dailypost').html('<a href="'+ e.permalink +'" class="title">'+ e.title +'</a><p class="text-italic">Daily Post for '+ date +'</p><div class="post-content"><p>'+ e.excerpt +'</p><a href="'+ e.permalink +'" class="btn btn-primary">Continue reading <span class="fas fa-caret-right fa-xs fa-fw"></a></div>');
        })
        .fail(function() {
            console.log("error");
        });
        
    });
});

// This function will run on load to show appropriate post for today's date
function getDailyPost() {

    var options = { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' };
    var current = new Date();

    var month = current.getMonth() + 1;
    var day = current.getDate();
    var date = new Date(current.getFullYear(), (month - 1), day).toLocaleDateString("en-US",options);
    
    jQuery.ajax({
        url: '/wp-json/reazul/v1/daily_post',
        dataType: 'json',
        data: {for_day: day, for_month: month},
    })
    .done(function(e) {
        jQuery('.dailypost').html('<a href="'+ e.permalink +'" class="title">'+ e.title +'</a><p class="text-italic">Daily Post for '+ date +'</p><div class="post-content"><p>'+ e.excerpt +'</p><a href="'+ e.permalink +'" class="btn btn-primary">Continue reading <span class="fas fa-caret-right fa-xs fa-fw"></a></div>');
    })
    .fail(function() {
        console.log("error");
    });
}
// Calling the function on page load
if (window.addEventListener)
   window.addEventListener("load", getDailyDevotional, false);
  else if (window.attachEvent)
   window.attachEvent("onload", getDailyDevotional);
  else window.onload = getDailyDevotional;