adatta02

class HttpRequest {
  readonly url : string;  
}

const req = new HttpRequest();
req.url = "http://www.setfive.com";

adatta02

type MyNotification = Email | SMS | VoiceRecording | BulkMessage;
class Email {}
class SMS {}
class VoiceRecording {}
class BulkMessage {}

function assertNever(error : never) : string {
  throw Error("Invalid: " + error);
}

adatta02

type MyNotification = Email | SMS | VoiceRecording;
class Email {}
class SMS {}
class VoiceRecording {}
class BulkMessage {}

function assertNever(error : never) : string {
  throw Error("Invalid: " + error);
}

adatta02

function showNotification(notification){
    if(notification instanceof Email){
        return "You got an email from $email with title: $title";
    }else if(notification instanceof SMS){
        return "You got an SMS from $number! Message: $message";
    }else if(notification instanceof VoiceRecording){
        return "you received a Voice Recording from $name! Click the link to hear it: $link";        
    }
}

adatta02

// From https://docs.scala-lang.org/tour/pattern-matching.html

def showNotification(notification: Notification): String = {
  notification match {
    case Email(email, title, _) =>
      s"You got an email from $email with title: $title"
    case SMS(number, message) =>
      s"You got an SMS from $number! Message: $message"
    case VoiceRecording(name, link) =>
      s"you received a Voice Recording from $name! Click the link to hear it: $link"

adatta02

function getPartyGuests() : string[] {
    if(Date.now() % 2 == 0){
        return [];
    }else {
        return null;
    }
}

const myGuests : string[] = getPartyGuests();
myGuests.push("Ashish");

adatta02

<?php

$clientIds = [111929, 372530, 180565];
for($i = 0; $i < 100; $i++){
    $clientIds[] = rand(1, 100000);
}
$clientIds = array_values(array_unique($clientIds));

$values = [];
for($i = 0; $i < 5000000; $i++){

adatta02

mysql> ALTER TABLE client_order ADD COLUMN date date default null;
Query OK, 0 rows affected (46.72 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> UPDATE client_order SET `date` = STR_TO_DATE(DATE(created_at), "%Y-%m-%d");
Query OK, 5000000 rows affected (9 min 52.98 sec)
Rows matched: 5000000  Changed: 5000000  Warnings: 0

mysql> ALTER TABLE client_order ADD INDEX date_client_idx (date, client_id);
Query OK, 0 rows affected (29.43 sec)

adatta02

mysql> EXPLAIN SELECT SUM(total), client_id FROM client_order WHERE client_id IN (111929, 372530, 180565) AND created_at >= "2016-12-24 00:00:00" AND created_at <= "2016-12-25 24:59:59" GROUP BY client_id;
+----+-------------+--------------+------------+-------+----------------------------------+------------+---------+------+--------+----------+------------------------------------+
| id | select_type | table        | partitions | type  | possible_keys                    | key        | key_len | ref  | rows   | filtered | Extra                              |
+----+-------------+--------------+------------+-------+----------------------------------+------------+---------+------+--------+----------+------------------------------------+
|  1 | SIMPLE      | client_order | NULL       | range | client_idx,created_at_client_idx | client_idx | 5       | NULL | 281308 |    15.22 | Using index condition; Using where |
+----+-------------+--------------+------------+-------+----------------------------------+-----------

adatta02

mysql> ALTER TABLE client_order DROP INDEX client_id_created_at_idx;
Query OK, 0 rows affected (0.06 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> ALTER TABLE client_order ADD INDEX created_at_client_id_idx (created_at, client_id);
Query OK, 0 rows affected (20.21 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> EXPLAIN SELECT SUM(total), client_id FROM client_order WHERE client_id IN (111929, 372530, 180565) AND created_at >= "2016-12-24 00:00:00" AND created_at < "2016-12-25 00:00:00" GROUP BY client_id;
+----+-------------+--------------+------------+-------+----------------------------------+-----------------------+---------+------+------+----------+--------------------------------------------------------+