Dotnotes: JavaScript ES6 Syntax - Amy Peniston · 2020. 6. 11. · let...

Post on 04-Feb-2021

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  • TEMPLATE STRINGS youcanalsouseline

    JAVASCRIPT Easilyembedvariables expressions breakswithinbacktickstocreatemultilinestrings

    E S 6 Thecactusisnamed name Nomore inSYNTAX

    ARROWFUNCTIONS TherearemanyHTheBigPicturekESGaddsnew Aconcisesyntaxforcreatingfunctions syntacticvariationsdeclarativesyntaxwhichshiftsour 1focusawayfromimperative letsum functionab letsum ab atbimplementationdetails allowsus returnatbtowritehigherlevelmore 3 i Arrowfunctionsdonotbindtheirowninterpretablecode this rathertheyinheritonefromtheir

    todeclarevariablesthatwill Parent lexicalscopingSCOPING beusedinawidercontext i Justbecauseyoucanuseshorthand

    containthisvariablewithin doesn'tmeanyoushouldReadabilityfirsttheimmediatefunctionscopelet us Vanya tocreateablockscopedconstant

    variablethatcannotbereassignedToenforceblockscoping ratherthan COLI signalintentthisvariablewillnotchangerelyingonstylisticconventions i thisdoesnotmeanthatthevalueofthevariableisimmutable

    containthisvariablewithinthisblockscope i Mustbeinitializedwithavalue

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    Giorgioc.is iiiEehsz Elisha.io 9ieiiiiiniiePiiii.eiiioRvariablesonlyexistwithintheirenclosingblockdenotedby 3 Inanassignmentcontext transformsanindefinitewww.J listofargumentsintoaproperarray

    function fool args aras isanarrayofallparameterspassedDESTRUCTURING intothefunctionExtractdatafromarrays objects let s m i2,33 m 2,33AExtractIstaznd itgathersthelet first second myArr elementsfrom restofthe

    myArr Otherwise i expandsaniterable elements

    let a b myobj Extractpropertiesa b frommyob fool args Passtheelementsofanarrayintoafunction

    Thisisjustthetipoftheicebergwhenitcomestodestructoring leta 1.2.33 succintarrayb Coil2,33 creationletb 0 a

    DEFAULTVALUESif novalve or undefined ispassed CONCISEPROPERTIES METHODS

    varob Eliminateduplicativecodeinobjectsfunctionspam n l Defaultvalueassigned ainfunctionhead whenthepropertyname valuenameb t shorthandformethoddefinitionslet a 42 b c ham Adefaultvaluecanalsobepassedwhendestructuring