PHP debug checklist

checklist_debug.php

<?php
/**
 * File to remind myself what things may come handy
 * while I get stuck somewhere and don't have idea
 * why things aren't working. These tricks may help you
 * know the cause and solve the issue
 **/

//Checklist 1: Sometimes, your json_encode may return null or false. 
//So to know if there is some issue in json_encode itself, use this switch below
$a = json_encode($b); //or $a = json_encode($b, JSON_UNESCAPED_UNICOD);
switch (json_last_error()) {
        case JSON_ERROR_NONE:
            echo ' - No errors';
        break;
        case JSON_ERROR_DEPTH:
            echo ' - Maximum stack depth exceeded';
        break;
        case JSON_ERROR_STATE_MISMATCH:
            echo ' - Underflow or the modes mismatch';
        break;
        case JSON_ERROR_CTRL_CHAR:
            echo ' - Unexpected control character found';
        break;
        case JSON_ERROR_SYNTAX:
            echo ' - Syntax error, malformed JSON';
        break;
        case JSON_ERROR_UTF8:
            echo ' - Malformed UTF-8 characters, possibly incorrectly encoded';
        break;
        default:
            echo ' - Unknown error';
        break;
}

/**
 * Remember when you want to output something on page, it must be properly encode and escaped. 
 * Sometimes, when your output contains unicode characters and if you haven't encoded it properly, 
 * it will not output anything, leaving you all confused and less hairs on your head. 
 **/
$html_content = htmlentities(stripslashes(utf8_encode($html_content)));