The document provides biographical information about Viktor Turskyi, including his professional experience as a non-executive director, founder, senior software engineer, and open source developer with over 20 years of experience in IT. It also lists some of his conference talks and delivered projects. The remaining slides provide examples and explanations of JavaScript and Perl concepts like data types, operators, functions, objects and arrays.

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2. Viktor Turskyi
● Non-executive Director at WebbyLab
● Founder at my-talks.net
● Senior Software Engineer at Google
● Open source developer
● More than 50 conference talks
● 20 years of experience in IT
● Delivered more than 80 projects of different
scale (including projects for 5 companies from
Fortune 500 list)
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3. array.filter, array.map, array.reduce, array.forEach, array.indexOf
JSON.parse, JSON.stringify
Date.now
getters, setters
https://kangax.github.io/compat-table/es5/
JavaScript ES3 to ES5
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4. Classes,
Spread parameters, rest operators
Destructuring,
const, let
Arrow functions,
Promise, Set, Map etc
https://kangax.github.io/compat-table/es6/
JavaScript ES5 to ES6
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5. https://stackoverflow.com/questions/7937/how-to-solve-the-select-overlap-bug
-in-ie6
Asked 13 years, 3 months ago
How to solve the select overlap
bug in IE6?
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6. Let’s learn a little bit of Perl

7. A little bit of typing?
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8. Weak typing + Monomorphic operators
# Weak typing + Monomorphic operators
print 1 + 1;
print '1' + 1;
print '1' + '1';
print "1" + '1' == 2;
print 1 . 1;
print '1' . 1;
print '1' . '1';
print "1" . '1' eq 11;

9. Primitives
# Strings
print 'This is a test.';
print "Hi there!n";
# Variables, "$" = scalar
my $animal = "camel";
my $answer = 42;
# Arrays, "@" = array
my @numbers = (0..10_000); # ".." - sequence
my @animals = ("camel", "llama", "owl");
print $animals[0]; # prints "camel"
# Hashes, "%" = hash, "=>" is fat comma
my %fruit_color = ( apple => "red", banana => "yellow");
print $fruit_color{'apple'}; # prints "red"

10. Slices
# Slices
my @animals = ("camel", "llama", "owl");
print @animals[0, 2];
my %fruit_color = ( apple => "red", banana => "yellow");
print @fruit_color{'apple', 'banana'};

11. Context
# Context (scalar, list, void)
# for array
print @animals; # list context
my $animal_cnt = @animals; # scalar context
print scalar @animals; # forced scalar context
# for hash
my %fruit_color = ( apple => "red", banana => "yellow");
print %fruit_color; # list context
print scalar %fruit_color; # forced scalar context
# Default variable $_
foreach (@animals) { print "1: $_n" }
foreach my $a (@animals) { print "2: $an" }

12. Step 1: I show a task
Step 2: You try to solve it in JS
Step 3: I show solution in JS an Perl
Let’s play a game
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13. https://paiza.io/en/projects/new?language=perl
https://paiza.io/en/projects/new?language=javascript
Playgrounds
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14. Cases

15. Increment variable by 10000
Set variable to 10000 if contains falsy value, otherwise leave as is
Set variable to 10000 if it is node defined
Case 1: Logical assignment
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16. JavaScript solution
let variable = 0;
variable += 10000;
variable = variable || 10000;
// ES2021
variable ||= 10_000;
variable ??= 10_000;

17. Perl solution
my $variable = 0;
$variable += 10_000;
$variable ||= 10_000;
$variable //= 10_000;

18. Merge objects o1 with o2 into o3
Case 2: Merge hashes
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19. JavaScript solution
const o1 = {A: 1, B: 2};
const o2 = {C: 3, D: 4};
// With new method
const o3 = Object.assign({}, o1, o2);
// With new syntax
const o3 = {...o1, ...o2};

20. Perl solution
my %o1 = (A => 1, B => 2);
my %o2 = (C => 3, D => 4);
my %o3 = %o1, %o2;

21. const users = [
{id: 1, name: 'Viktor' },
{id: 2, name: 'John' }
];
{ '1': { id: 1, name: 'Viktor' }, '2': { id: 2, name: 'John' } }
Case 3: build lookup table
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22. JavaScript solution
const users = [
{ id: 1, name: 'Viktor' },
{ id: 2, name: 'John' }
];
const usersById = Object.fromEntries( users.map(u => [u.id, u]) );

23. Perl solution
my @users = (
{ id => 1, name => 'Viktor' },
{ id => 2, name => 'John' }
);
my %users_by_id = map { $_->{id} => $_ } @users;

24. letters2codes = { a: “1”, b: "2" };
codes2letters = {“1”: "a", “2”: "b" };
Case 4: Swap keys and values in
object
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25. JavaScript solution
const letters2codes = { a: '1', b: "2" };
const codes2letters = Object.fromEntries(
Object.entries(letters2codes).map(([k, v]) => [v, k])
);

26. Perl solution
my %letters2codes = (a => '1', b => "2");
my %codes2letters = reverse %letters2codes;

27. Sort array numerically
Sort array by value length (longest first), if the length is equal then
sort alphabetically (a to z)
Case 5: Sort array
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28. JavaScript solution
const numbers = [10, 4, 3, 9, 8];
const sorted = numbers.sort((a,b) => a - b);
const words = ['cat', 'dog', 'cow', 'parrot', 'camel'];
const localCmp = (a, b) => {
// Ternary operator will make sorting "unstable"
if (a > b) {
return 1;
} else if (a < b) {
return -1;
} else {
return 0;
}
};
const sortedWords = words.sort((a, b) => {
return b.length - a.length || localCmp(a, b);
});

29. Perl solution
my @numbers = (10, 4, 3, 9, 8);
my @sorted = sort { $a <=> $b } @numbers;
my @words = ('cat', 'dog', 'cow', 'parrot', 'camel');
my @sorted = sort { length($b) cmp length($a) || $a cmp $b } @words;

30. const fruitColor = { apple: "red", banana: "yellow", kiwi: "green"};
[‘red’, ‘yellow’, ‘green’]
Case 6: List values from object by
keys sorted alphabetically
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31. JavaScript solution
const fruitColor = { apple: "red", banana: "yellow", kiwi: "green"};
const values = Object.keys(fruitColor).sort().map(k => fruitColor[k]);

32. Perl solution
my %fruit_color = ( apple => "red", banana => "yellow", kiwi => "green");
my @values = @fruit_color{sort keys %fruit_color};

33. Questions?

34. Telegram: @JABASCRIPT
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35. Follow me:
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my-talks.net/viktor-turskyi

36. Email
viktor@webbylab.com
Website
https://webbylab.com
@koorchik
@koorchik
My contacts
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