On Thursday, February 8, at 19:00, the first UralJS meeting in 2018 will be held in the co-working “Sol”. Let us see why TypeScript won Flow in Contour, listen to optimization recipes from Lyosha Ivanov, an evil Martian and a member of Fronttalks program committee, and argue that this is better: functionalism or OOP.

UralJS appeared as an experiment - a group of colleagues lacked professional movement, and we decided to organize it. For the first time, 70 developers gathered, and now we are closing registration for a hundred participants, because the platforms are not rubber. The geography is expanding - guests from Tyumen, Chelyabinsk and Perm came to us in Yekaterinburg.

For 2017, we conducted 5 meetings. They discussed what to do if the small pet project attracted a million users , told them what a cool Vue was and immediately bombed it , dealt with internationalization and admired the flows in JS . In the summer we tried other formats. Andrei Starovoit from JetBrains gave a great talk on how WebStorm developers choose technologies for support. Together, at weekend, we coded Angulyar and solved the same problem five times with different partners and restrictions .

What will happen this time:

Nikolay Karev, freelancer - this is evil

The use of the this keyword in JS is an indicator of potential problems associated with introducing an implicit state or dependencies within a class. I will show how to find these problems and solve them using tools from functional programming.

Mikhail Shatihin, Contour - Ruthless Typing

Let's talk about typing applications on TypeScript. I'll show you how to add types from scratch to a Redux application and get maximum control over the application. I will show why you can write fewer tests in a typed application and errors of certain classes completely disappear from it - if compiled, it just works. I will reveal the negative side: I will tell you how much the development time and the size of the code base increases. I will explain how types help attract backenders to the development of the frontend.

Alexey Ivanov, Evil Martians - React and Data: Effective ways to store and change the state

When JSX is compiled into JS, functions are obtained. One functions are enclosed in others, others are enclosed in the third. If you call the topmost function, you will first get VirtualDOM, and then just the DOM.

So far so good. But now we need to change some data in the application, and change our DOM based on them. And here begins the different nuances. Are all changes equally useful? Which edits will the rerender cause and which ones will not? How does React choose what to change? What changes in VirtualDOM will DOM changes bring, and which ones won't? How to organize your data so that the application runs as fast as possible?

If when you enter data in the text field, the whole application starts to slow down, checkboxes are set for half a second, and the animations slow down, then my report will be useful to you.

Participation is free, but you must register so that the organizers prepare tea, coffee and snacks for all guests.

Registration is here .

Records will appear on the YouTube channel after the mitap.