05 You Don't Know JS：Async&Performance.pdf

drink,becausecomfortisimportant,butonceI'mpastthebitaboutthecandidate'sfluidin/out-take,Isetaboutdetermining

ifthecandidateknowsJavaScript,orjustjQuery.

Notthatthere'sanythingwrongwithjQuery.ItletsyoudoalotwithoutreallyknowingJavaScript,andthat'safeaturenota

bug.ButifthejobcallsforadvancedskillsinJavaScriptperformanceandmaintainability,youneedsomeonewhoknows

howlibrariessuchasjQueryareputtogether.YouneedtobeabletoharnessthecoreofJavaScriptthesamewaytheydo.

IfIwanttogetapictureofsomeone'scoreJavaScriptskill,I'mmostinterestedinwhattheymakeofclosures(you'veread

thatbookofthisseriesalready,right?)andhowtogetthemostoutofasynchronicity,whichbringsustothisbook.

Forstarters,you'llbetakenthroughcallbacks,thebreadandbutterofasynchronousprogramming.Ofcourse,breadand

butterdoesnotmakeforaparticularlysatisfyingmeal,butthenextcourseisfulloftastytastypromises!

Ifyoudon'tknowpromises,nowisthetimetolearn.Promisesarenowtheofficialwaytoprovideasyncreturnvaluesin

Fordessert,well,Iwon'tspoilthesurprise,butpreparetogazeintothefutureofJavaScript!Featuresthatgiveyoumore

andmorecontroloverconcurrencyandasynchronicity.

Well,Iwon'tblockyourenjoymentofthebookanylonger,onwiththeshow!Ifyou'vealreadyreadpartofthebookbefore

readingthisForeword,giveyourself10asynchronouspoints!Youdeservethem!

DeveloperAdvocateatGoogleChrome