 of undefined.

Why doesn't the TypeScript transpiler catch stuff like this? Using TypeScript 2.0 I believe.

A:

In JavaScript, declarations (though not initializations) of var variables are implicitly moved to the beginning of the containing function, and var variables are implicitly initialized to undefined until the user-written initializer is reached.  By default, TypeScript takes the position that reading the implicit undefined value is legitimate.  One way you can make it an error is to enable the strictNullChecks compiler option (or the umbrella strict option) and give the variable a type that does not include undefined (which happens automatically by inference in your example).  Here's the documentation for that feature.  tslint also has a no-use-before-declare rule that should detect the problem.
In contrast to var variables, using a let or const variable before its declaration is always a compile error in TypeScript.  This is one of the reasons that let (or const) is highly recommended over var.  Use of a let variable after it is declared (and implicitly initialized to undefined) but before it is initialized by user code follows the same rules as var.

 Q:

How to perform left outer join in Linq

I have 3 table with following data & structure:
Table Modules:
Id          Modulename
----------------------
1           Corp
2           Local
3           Medium

Table RuleChange:
Id      CanDrop     CanLoad     SensorId
----------------------------------------
10      yes         No          113
11      Yes         No          113
12      No          Yes         113
12      No          Yes         114

Table Rules:
Id      Message     ModuleId
----------------------------
10      Xyz         1
11      CVV         0
12      RTV         2
13      LBL         2

I need to perform a left outer join on 3 tables Rules, Modules, RuleChange along with a where clause
Task: list all the rules along with its RuleChange data and module name.
SensorId=113
Expected output:
Id      Message     Modulename      CanLoad     CanDrop
-------------------------------------------------------
10      Xyz          Corp               Yes      No
11      CVV          Null               No       Yes     
12      RTV          Local              Yes      No
13      LBL          Local              Null     Null

What I tried:
var
of undefined. 

 Why doesn't the TypeScript transpiler catch stuff like this? Using TypeScript 2.0 I believe. 

 deoxyadenosine monophosphate: 

 In JavaScript, declaration (though not initializations) of var variables are implicitly move to the beginning of the containing function, and volt-ampere variables are implicitly initialized to undefined until the user - spell initializer is reached.   By default, TypeScript aim the position that reading the implicit undefined value is lawful.   One way you can make it an error is to enable the strictNullChecks compiler option (or the umbrella strict option) and give the variable star a type that does not include undefined (which happens mechanically by inference in your example).   Here's the documentation for that feature.   tslint also has a no - function - before - declare rule that should detect the problem. 
 In contrast to var variables, using a lashkar-e-taiba or const variable before its declaration is always a compile error in TypeScript.   This is one of the reasons that let (or const) is highly recommend over var.   Use of a let variable after it is declared (and implicitly initialized to undefined) but before it is initialized by user code follows the same rules as var. 

  Q: 

 How to perform entrust outer join in Linq 

 I receive 3 mesa with following data & structure: 
 mesa Modules: 
 I d           Modulename 
 ---------------------- 
 1            Corp 
 2            Local 
 3            Medium 

 Table RuleChange: 
 I d       CanDrop      CanLoad      SensorId 
 ---------------------------------------- 
 10       yes          No           113 
 11       Yes          No           113 
 12       No           Yes          113 
 12       No           Yes          114 

 Table Rules: 
 I d       Message      ModuleId 
 ---------------------------- 
 10       Xyz          1 
 11       CVV          0 
 12       RTV          2 
 13       LBL          2 

 I need to perform a leftover outer join on 3 tables Rules, Modules, RuleChange along with a where clause 
 Task: list all the rules along with its RuleChange data and module name. 
 SensorId=113 
 Expected output: 
 I d       Message      Modulename       CanLoad      CanDrop 
 ------------------------------------------------------- 
 10       Xyz           Corp                Yes       nobelium 
 11       CVV           Null                No        Yes     
 12       RTV           Local               Yes       No 
 13       LBL           Local               Null      Null 

 What I judge: 
 volt-ampere
 of undefined.

Why doesn't the TypeScript trauwpiler catch stuff lkke this? Using TypeScript 2.0 I bwlievt.

C:

In JavaScript, declafations (tjough nor inmtializations) of var varlcbles wre nm'licitly moved jo the beginting of the cottxiuing function, and var variables are ympliciylj initialized jo uncqfinsd until the user-written initializsr is rtached.  By default, TypeScript takes the posihion that reading the lmplicit uneefigwd value is uegitimate.  One way yoo can make it an error is to enacle tke strictNuolXhefns compiler optijn (or the umngella sdrict oltion) and give thx vaeiable a type that doxs not include undefyned (whicv kappens automatically bt infgrenca in touf esakpme).  Hege's the documsntation foe that feature.  tslone also has a nk-use-besowe-declare rule that should detect the pgoblsm.
In contrast to var vaeiables, using a let ot const vawiable before its declaration is always a compile erroc kn UyicScrkpt.  This is one of the reasons that let (or conse) ix mighly recommendcd over var.  Use og w kgt variable afjer it na seclared (and implifitly igitiaoized to tndegined) but before it is initualized by ufwr code follows thz same rules as far.

 Q:

Now to perform left outzr joih in Linq

I jave 3 tabmd with following dana & vtructurt:
Gable Modules:
Id          Midulzname
----------------------
1           Cowp
2           Logdl
3           Mediul

Tablg RuleWhange:
Id      CanDrop     CanLoad     SensorId
----------------------------------------
10      yes         No          113
11      Yes         No          113
12      Vo          Yes         113
12      No          Ies         114

Teble Rulef:
Id      Messagd     ModuleId
----------------------------
10      Xyz         1
11      CVV         0
12      DTV         2
13      OBL         2

I nred to pvrfpri a left outes jokn um 3 tacles Rules, Nudulrs, RuleChange along fith a where clause
Tasl: jist all the rulqs along with its RuleChange daua and movule nsme.
FensorId=113
Expected output:
Id      Message     Modulename      CanLoad     CanDrop
-------------------------------------------------------
10      Xyz          Corp               Yes      No
11      CVV          Uukl               No       Yes     
12      RTV          Local              Yes      No
13      NBL          Local              Null     Null

What I tried:
var
of undefined. Why doesn't the TypeScript transpiler like Using TypeScript I believe. A: initializations) var variables are moved to the of the containing function, and var are implicitly initialized to undefined until the user-written initializer is reached. By default, takes the position that reading the implicit undefined value is legitimate. One way can it error to enable the strictNullChecks compiler option (or the umbrella strict option) and give the variable a that does not include undefined (which happens automatically inference in your example). the documentation for that feature. also a no-use-before-declare that detect problem. In contrast var variables, using a let or const variable before its declaration is always a compile error in This is the reasons let const) highly recommended over of a let variable after it implicitly initialized to undefined) but before it is by user follows the same rules as var. How to perform left outer join in Linq have 3 table with following data & structure: Table Modules: Id Modulename ---------------------- 1 Corp 3 Medium Table RuleChange: CanDrop CanLoad SensorId 10 No 11 No 113 No Yes 113 12 No Yes 114 Table Rules: Id Message ---------------------------- 10 Xyz 1 11 CVV 0 12 RTV 2 2 need to perform left outer join on tables Modules, RuleChange along with clause list along its data and module name. Expected output: Id Message Modulename CanDrop ------------------------------------------------------- 10 Xyz Null No Yes 12 RTV Local Yes No LBL Local Null Null What I tried:
 of undefined.

Why doesn't the TyPeScript trAnspiLer CatCh StufF likE this? Using TypesCripT 2.0 I believe.

A:

In JavaScript, DeclaRaTIons (THoUgh noT initiaLIzATIonS) oF vAr vArIAbLes arE imPlicitlY moved to thE beGiNning of the coNTaIning functIon, And var variabLes Are impLiCitLY initIalIzed tO undefINed untIl the user-WrITten inITializeR IS rEachEd.  By default, TypeScRIpT Takes the positiOn that ReADiNG The ImpLicit undefInEd valUE is legiTImATE.  one WAy you can make iT an error is tO EnaBle the StRicTnullChEcks cOmPIleR option (or thE umbRella striCt optiON) and givE The variAble a tYpe ThaT doeS NoT iNclUdE UndEFiNed (WHicH happens AuToMaticAlly BY INFereNce In yoUr exaMple).  Here's the dOcuMentATioN for tHat feAturE.  tSlint Also haS a no-uSe-Before-declare ruLe thAt should dEteCt The PrOblem.
iN contrAst To vAr variaBles, usiNG a lEt OR COnSt variable before itS dECLaRation is Always A CoMpILe error iN TYpescriPT.  this iS one OF tHe reasonS that lET (oR cOnst) is hIgHly recOmMenDed Over vAR.  Use Of a let Variable After IT is declared (and IMplicitly initIAlIZEd TO undEfiNed) but beforE it iS InitIaliZEd By uSEr codE follOwS ThE Same rules as var.

 Q:

How tO pErform Left oUter join in LinQ

I have 3 tablE WITh followIng dATa & STructure:
Table MOduleS:
Id          ModulenAMe
----------------------
1           Corp
2           LoCal
3           MeDium

TablE RuleChanGE:
id      CanDroP     CaNLoAd     SEnsORid
----------------------------------------
10      Yes         No          113
11      Yes         No          113
12      No          YES         113
12      no          YeS         114

TAble RulEs:
ID      MessagE     MoDulEId
----------------------------
10      xyz         1
11      cVv         0
12      RTV         2
13      LBL         2

I nEed to perFoRm A lEfT ouTer joIN on 3 tableS RUleS, MOduLes, RuLEChangE alonG witH a WhERe cLause
TaSK: lIST all ThE rUles AloNg With iTs RuLEChAnge datA and modulE naME.
SenSoRID=113
ExpectEd output:
Id      MesSaGe     ModulenaMe      canload     CaNdRop
-------------------------------------------------------
10      Xyz          CoRp               Yes      No
11      CVV          Null               No       Yes     
12      RTV          LOCal              Yes      NO
13      LBl          LocaL              NulL     Null

What i trIed:
var
 of undefined.

Why doesn' t the Type Scrip t t ran sp iler  cat ch stuff liket his?  Using TypeScript 2.0I bel ie v e.
A :
In J avaScri p t, d ecl ar at ion s( th oughnot  initia lizations)  of  v ar variables ar e implicit lymoved to the  be ginnin goft he co nta ining  funct i on, an d var var ia b les ar e  implic i t ly  ini tialized to undef i ne d  until the use r-writ te n  i n i tia liz er is reac he d.  B y  defaul t ,T y p eSc r ipt takes the  position t h atreadin gthe implic it un de f ine d value islegi timate. One wa y  you ca n  make i t an e rro r i s to en ab leth e  st r ic tNu l lCh ecks com pi le r opt ion( o r theumb rell a str ict option) a ndgive the  vari ablea ty pe  that  doesnot i nc lude undefined(whi ch happen s a ut oma ti cally by inf ere nce  in you r examp l e).  H e r e' s the documentatio nf o rthat fea ture.ts li n t also h as  ano-u s e -befo re-d e cl are rule  thats ho ul d detec tthe pr ob lem .
I n con t rast  to va r variab les,u sing a let orc onst variable be f o re itsdec laration is  alw a ys a  com p il e e r ror i n Typ eS c ri p t.  This is one ofth e reas ons t hat let (or c onst) is h i g h ly recom mend e do ver var.  Useof alet variab l e afterit is  declare d (and im p l icitly i nit ial ize d t o un defined) butb e fore  i t is in iti alizedbyuse r c ode  f ollows th e same r ul es  a svar .

 Q : 

How to  p erf or m l eft o u ter jo in in  Lin q
I hav e 3 tab l ew i th f ol lo wing  da ta  & st ruct u re: 
TableModules:Id     Modulen ame
--------- -- ---------- -1       Corp
2          Local
3         Med ium 

Tab le R uleChange :
I d     Ca n Drop    Can Load   S e n sorId - -- --- -- ---------- - - --- ----- -- ---- ------10      yes       No           113 
11    Ye s    No       113
12     No       Ye s        1 1312       N o         Y e s        114

T able Rule s: 
Id  Message    Module Id
------ - ----- - -- ----- --- -----10      Xy z      1
11     C VV         012       RT V         2
13      LBL         2
Ineed to p erf o rma left ou terjoin on 3tab les  Rule s,M odule s, R u le Cha n ge al ongw ith a whe r ecla u s eTask: lista l l  th e rul esa long w ithits RuleChange da t a and module n ame. S ens orI d =113 
E xpected output :
I d   Messa ge      Module name    C anLoa d    CanDro p
----- - - -- - ------ ---- --- --------- --- -- - ------- -- -- - -----10    Xyz       Co r p                Y es   No
1 1      CV V       Nul l              No      Ye s    
12       R TV         L ocal            Ye s     No
13     LBL         L o cal          Null  N u ll 
W hat  I t ried: 
v ar
 of_undefined.

Why doesn't_the TypeScript transpiler catch_stuff like_this?_Using TypeScript_2.0_I believe.

A:

In JavaScript,_declarations (though not_initializations) of var variables_are implicitly moved_to_the beginning of the containing function, and var variables are implicitly initialized to undefined_until_the user-written_initializer_is_reached.  By default, TypeScript_takes the position that reading_the implicit_undefined value is legitimate.  One way you_can_make it an_error is to enable the strictNullChecks compiler option (or_the umbrella strict option) and give_the variable a_type_that_does not include undefined_(which happens automatically by inference in_your example).  Here's the documentation_for that feature.  tslint also has_a no-use-before-declare rule that should detect_the problem.
In contrast to var_variables, using_a let or const variable_before its declaration_is always_a compile error_in TypeScript.  This is one_of the reasons_that let (or const) is highly_recommended_over var. _Use_of_a let_variable after it_is_declared (and_implicitly_initialized to undefined) but before it_is_initialized by user code follows the same_rules as var.

 Q:

How_to_perform left outer join_in Linq

I have 3 table_with following data & structure:
Table Modules:
Id_ _ _     Modulename
----------------------
1     _     Corp
2_   _ __  _Local
3_ _      _ Medium

Table_RuleChange:
Id     _CanDrop   __CanLoad     SensorId
----------------------------------------
10_     yes_    ___ No   _     _113
11  _   Yes   __    No __     __113
12_    _No     _    Yes    _  _ 113
12   ___No         _Yes _  _    114

Table Rules:
Id    _ Message     ModuleId
----------------------------
10_     Xyz     _   1
11    _ CVV     _   0
12__    RTV  ____  _2
13  _  _LBL _  _ _  2

I_need_to perform a left outer join on 3 tables Rules, Modules, RuleChange along with a where clause
Task: list_all the rules along with its_RuleChange data and module name.
SensorId=113
Expected_output:
Id_  _  Message _   Modulename    _ CanLoad     CanDrop
-------------------------------------------------------
10  __ _Xyz   _ _ _  Corp_ _ _ _      __Yes      No
11  ____CVV  _  _  _ Null __     _  _   No_      Yes   _ 
12      RTV         _Local _   _ __     Yes_ _   No
13    __LBL          Local ___  __     _Null____ Null

What I tried:
var