JavaScript: typeof - kufunikira kapena mwayi

Pali ntchito kukhala mtundu makamaka deta, ndipo ankachita chidwi ndi processing awo kuti alandire zotsatira. The ulamuliro wa "maganizo atypical mu mafotokozedwe" mwadzidzidzi, koma mwachibadwa. Pre-variable kulengeza salinso kuvomerezedwa, ndi kumasonyeza mtundu wake onse wataya tanthauzo, osachepera ku opareshoni imene nawo.

Mapulogalamu anakumasulani manja ake: si koyenera kuti tikalengeze chinthu pachiyambi. Nthawi zambiri yekha pa nthawi ya ntchito adzakhala kudziwa zoyenera kutenga, chochita ndi mmene. Koma mitundu, iwo "akhala mfundo," ie, kumakhaladi deta imene chimadaliranso chinthu!

Zikuyenera kapena alibe, chabwino, nanga bwanji izo

Kumasulira lophweka wa variable "AAA" ndipo zilipo aligorivimu kwa processing:

aaa ; var AAA;

( aaa ) { ngati (AAA) {
= 'I am!' Res = 'Ine mbuyanga!' ; // INE NDINE!
{ } Enanso {
= 'me no...' ; Res = 'ine ...'; // Ndilibe
}

Iwo amapereka chifukwa kuti: ". Ine sindiri" Apa kufunika kwa ntchito JavaScript typeof = CHOSADZIWIKA. Monga akufotokoza variable - "kuchita kanthu" sizikutanthauza. Kumene, pamene AAA = 1, ife tikufika: 'Ine ndine', koma ngati AAA = 0, zidzakhala ngati m'nkhani yoyamba: "Ine sindiri ...." mfundo wodabwitsa, masamu, komanso nzika yosavuta, ndipo sanathe kuganiza kuti phindu ziro ali ndi tanthauzo losiyana kwathunthu kusiyana ndi lenileni. Only amakono (atypical) mapulogalamu amatha maganizo kufika!

JavaScript Design typeof, komanso mawu wanzeru koposa ngati (AAA) {... × ...} wina {... Y ...}, ali ndi makhalidwe kwambiri ogula ndi yabwino kwambiri kuti ntchito.

Pa peculiarities wa Chisililiki ndi alifabeti Latin

Professional mapulogalamu nthawizonse amakonda ndi English kujambula otchulidwa Russian, chifukwa siteji mapulogalamu chitukuko, pamene ena cybernetics expanses losadziwika modzipereka, koma m'madera ena a sayansi kompyuta anapita likunena phiri. Tinayamba kuchulukana ndi kukhala mapulogalamu zinenero, zochokera malembedwe 26 zilembo, komanso zizindikiro zina wamba.

Mophweka kwambiri ndi masoka anali malamulo mbadwa, linali labwino, angwiro, koma ndi zenizeni aliyense zomangamanga, ndi pamwamba pa zinenero lingaliro la portability kudutsa mapangidwe yomweyo anayamba mwamsanga. Izi limatsutsa kwambiri nthawi panopa: umboni analogue JavaScript typeof = CHOSADZIWIKA | chingwe | chiwerengero | Buliyani | sakugwirizana | ntchito ngati izo sizinali zophweka. zinenero zonse anali mosamalitsa ofunda, ndi malembedwe kwambiri ndiponso kupewa kukayika.

Mitundu, zosintha, ndi ntchito

Point ndi zofunika kwambiri. Kalembedwe ndi malongosoledwe a zosintha ndi - zofunika kwambiri chigawo chimodzi cha pulogalamu, ndi mapulogalamu sangathe kulemba aligorivimu ntchito, pamene naye zosiyanasiyana weniweni wa deta mu okhwima chithunzi mwamwambo chabe zosintha, magulu, zinthu ndi ntchito.

JavaScript umabala onse anapeza zaka mphamvu zinchito, machenjerero ake onse mwangwiro kusonyeza kuzindikira panopa malembedwe ndi malamulo yoyenera anaika mu manenedwe wake.

funso n'lakuti, pamene zimenezi ziyenera kuchitidwa pamene kuli kofunikira kuthandauza kwa mtundu lemba, JavaScript ntchito typeof. Kwenikweni options wochezeka lembani mameseji pang'ono: chingwe khalidwe ndi chiwerengero. Komabe, udindo wa chinthu lemba akhoza kuimba, ndipo ngakhale mizere ya kapangidwe array.join (), zomwe zikugwirizana mbali zonse mu mutu umodzi, ndiye, mu mzere umodzi.

Banal mawu akuti: pozungulira pali mtundu lemba, ndi JavaScript ntchito typeof ayenera kukhala pa nthawi yoyenera kuchita kufunika mtundu tanthauzo. Izi ndi zoona, koma kumapeto likukhalira ayi. JavaScript typeof chinthu adzakupatsani phindu chomwecho milandu itatu yonse:

aaa = {}; var AAA = {};
= typeof ( aaa ); Res = typeof (AAA);
+= '/' + typeof window . Res + = '/' + typeof zenera. ; chikalata;
+= '/' + typeof ( document . forms [ 0 ]); Res + = '/' + typeof (chikalata mitundu [ 0]).

Zotsatira: chinthu / chinthu / chinthu

Kugwiritsa akhoza typeof (AAA) ndi typeof AAA mtundu nyimbo - si zofunika, koma nthawi zonse yankho wapatsidwa, koma izo mwamtheradi sizikutanthauza chirichonse!

Kukayikakayika amakhala ndithu

Mapulogalamu mbali ya mphamvu achilendo: izo zouluka mofulumira kutsogolo kuti zoyenda lonse nthawi zonse poyamba. Nkhaniyo imapitirira miyezi, masabata kapena masiku, nthawi zina ngakhale maola. Ntchito yeniyeni mphamvu ya mapangidwe aligorivimu kwa kuthetsa chotero amakhala otanganidwa ndi wovuta pa kupitiriza kuti mapulogalamu ntchito mu mkhalidwe akhoza kukana zochita tsiku, sabata kapena kuposerapo.

Natural njira JavaScript typeof ndi mchitidwe wa chinthu wokonda mapulogalamu, amene malembedwe iyi ndi yosiyana ndi ofala mu zinenero pafupi ano, akugwiritsa pakati yokoka pa chinthu. zazikulu kwambiri mfundo: chilankhulo zimakhala kumanga chikukhudza manenedwe, osati malamulo syntactic.

deta mitundu Simple safuna kudziwa mtundu wake, kapena m'malo ntchito JavaScript typeof zokwanira. Ngati ndi kotheka, ndi pulogalamu yowongolera amasamalira masinthidwe polumikizana, koma kuti JavaScript typeof chinthu akupereka yankho lanzeru ndi chinthu ndi mtundu wa vuto - nkhawa wake! Izi mfundo zomveka kwa malingaliro zachikhalidwe za mapulogalamu zovuta amaonekera, koma ndi boma lenileni la zinthu.

Kusamalira malo - kudziwa mtundu wake, kusonyeza katundu wawo, motsatira njira zawo. Mapulogalamu kupukuta malembedwe anu, ndi mphindi iliyonse ya nthawi akugwiritsa pakati yokoka ya malembedwe anapanga ndi mapulogalamu manenedwe: dongosolo lake la zinthu kuti achite.