È You Dont Know JS Ù Download by ë Kyle Simpson

È You Dont Know JS Ù Download by ë Kyle Simpson Amazing book if you want to understand how asynchronicity or the illusion of asynchronicity in JavaScript works Kyle has a unique way of explaining deep technical CS concepts in a simple and straightforward manner He lays down the differences between concurrency, serialism and parallelism and then use those differences to explain the JS Event loop and then goes into the technicalities of implementation using callbacks, promises, and generators Finally, he gives some overview of assessing performance and benchmarking.
Quite technical, not at all light, very interesting read Although understanding promises and generators is quite handy, the last part about advanced patterns is one of those things that I m not sure when I ll end up using.
Still, while I personally appreciate knowing stuff, without worrying too much about when I ll find that knowledge useful, some pragmatic folks will probably skip those parts apendixes.
The chapter about promises is a little too preachy, promising that they will save us from callbacksonly to in the end, get to creating code that requires maybe a little too much mind bending.
Also, now it s december 2018 The async await keywords made it to the language maybe not sure.
.
I write python most of the time Many of the pat No Matter How Much Experience You Have With JavaScript, Odds Are You Don T Fully Understand The Language As Part Of The You Don T Know JS Series, This Concise Yet In Depth Guide Focuses On New Asynchronous Features And Performance Techniques Including Promises, Generators, And Web Workers That Let You Create Sophisticated Single Page Web Applications And Escape Callback Hell In The ProcessLike Other books In This Series, You Don T Know JS Async Performance Dives Into Trickier Parts Of The Language That Many JavaScript Programmers Simply Avoid Armed With This Knowledge, You Can Become A True JavaScript MasterWith This Book You Will Explore Old And New JavaScript Methods For Handling Asynchronous ProgrammingUnderstand How Callbacks Let Third Parties Control Your Program S ExecutionAddress The Inversion Of Control Issue With JavaScript PromisesUse Generators To Express Async Flow In A Sequential, Synchronous Looking FashionTackle Program Level Performance With Web Workers, SIMD, And AsmjsLearn Valuable Resources And Techniques For Benchmarking And Tuning Your Expressions And Statements La primera mitad se puede saltar si se entiende bien como funcionan las promesas, la segunda se pone mas interesante con los generadores y performance.
A fantastic exploration of what async means in the context of JavaScript I was amazed at the depth of explanation provided especially for the Promises chapter It is a gold mine in my opinion, one that I expect to be returning to again and again.
The author s take on Generators is pretty interesting Though I must confess, after a while, it started going a little above my head This only means that the text is dense and needs re reading This also makes me think how much of this can I apply in my day job Considering the goal of keep code readable simple, I am not very sure I will be using Generators anytime soon Async await looks fantastic and will certainly be useful in Node.
js based environments.
I expect Promises to be the bread and butter of all a This book should have ended with chapter 4.
Chapters 1 4 deal with the Async stuff.
Chapter 1 starts with a general introduction to concurrency and asynchrony and how it is managed in JavaScript via the event queue.
chapter 2 describes callbacks the pre ECMAScript 6 way to manage asynchrony and focuses on its limitations.
Chapter 3 details every possible aspect of Promises and how they solve the limitations of callbacks.
Chapter 4 deals with Generators another welcome new feature of ECMAScript 6 that helps in dealing with asynchrony and can be combined with Promises in useful ways.
So far so good nothing to complain about.
The next two chapters deal with the Performance part They discuss libraries that can help optimize and benchmark JavaScript code and provide suggestions on what is and is not meaningful to optimize and run benchmarks on.
Clear and easy to understand, this has helped me make sense of the often murky world of promises and generators It s very information dense but I found it easier to get to grips with by reading through a chapter and then going back and trying out the supplied code for myself The performance chapters didn t feel as in depth as the rest of the book but they did cover a few little things that the JavaScript engine will do to your code without you knowing eg unrolling recursion for you if it thinks a loop will run faster and things that you shouldn t spend time worrying about x or x They also went into how to use and not use benchmarking tests for checking your own code.
I must admit I got a bit lost on the last appendix advanced async patterns but I think that s because The most interesting thing today is that I got one question in my interview about Promise and it was covered in this book.
A few things from the top of my mind 1 Callbacks are no good, use them sometimes and avoiding nest them For many async task, try using Promise.
2 Promise tends to swallow errors so use it with async await3 Optimization my code is complicated than other devs suggest Using jsperf.
com or benchmarkjs to test my optimzation.
There are to this book that I have yet put into my mind but I don t have any plan to reread this one in foreseeable future The appendixes are about the author library asynquence which I guiltily skipped since I don t have any intention to take a loot at it For the 2 months, I think I will just focus on Promise and async await function Btw sorry generator function for misunderstanding you You are the precursor for the new async await since 2



You think you know JS read this book I have never imagined that there are so many concerns not with callbacks, but regarding promises as well Wonderful book on handling async requests via callbacks, promises and handling them via generators Kyle looks ahead a bit into ES7 async await features Last two chapters cover web performance, from general topics Web Workers, SIMD, asm.
js, to very specific ones benchmarking pieces of js code, figuring out crucial path I will definitely take a look at

Kyle Simpson is an Open Web Evangelist from Austin, TX, who s passionate about all things JavaScript He s an author, workshop trainer, tech speaker, and OSS contributor leader.