JavaScript: typeof - hei akiaki i te whai wāhi ranei

He whakamahia ki te waiho i te momo ngā o raraunga, a i te moni i roto i to ratou tukatuka i roto i te tikanga ki te whiwhi i te hua. Ko te mana o "whakaaro mohiotia i roto i ngā whakaahuatanga" haere mai ohorere, engari fakanatula. Ko ai ta mua-tāupe kore whakahauanga, a kua ngaro te tohu o tona momo i roto i te whānui auraa katoa, i te iti rawa ki te mahi i roto i nei uru reira.

wetekina ana rorohiko ona ringa: e kore te mea e tika ana ki te whakapuaki i te tahi mea i te timatanga. E mea pinepine anake i te wa o te whakamahi, ka waiho ki te whakatau he aha ki te tango, he aha ki te mahi me te pehea. Ko ngā momo, ratou ratou "Kua riro uara," arā, riro te reira raraunga runga nei hoki, tei runga te tahi mea!

He kore he, pai, ranei te aha o reira

He whakaahuatanga tino māmā o te tāupe "keee" me te hātepe e wātea ana mō te tukatuka:

aaa ; var keee;

( aaa ) { ki te (keee) {
= 'I am!' Res = 'Ko ahau!' ; // Ko ahau!
{ } Penei {
= 'me no...' ; Res = 'ahau kahore ...'; // E kore ahau e whai
}

E horo'a te reira i te mārama ngā: ". E kore ahau mahi" Here te uara o te mahi JavaScript typeof = kāore. whakaahua Just te tāupe - "mahi tetahi mea" e kore e tikanga. Ko e mo'oni, ka keee = 1, whiwhi tatou: 'Ko ahau', engari ki te keee = 0, ka waiho te reira i rite i roto i te take tuatahi: "E kore ahau mahi ...." kihai i taea e arorau Whakamiharo, he mathematician, me te he tangata ohie, ka whakaaro e te kore uara he tikanga tino rerekē atu i te kotahi tūturu. Ko te ahei o taua whakaaro maia hou (mohiotia) hōtaka anake!

JavaScript Hoahoa typeof, me te he faaiteraa atu maramarama ki te (keee) {... x ...} atu {... y ...}, he 'ulungaanga kiritaki pai, me te he tino watea ki te whakamahi i.

I peculiarities o Cyrillic me ngā arapū Latin

ka hiahia rorohiko ngaio tonu te reo Ingarihi pūāhua tuhi Russian, fakamātoato whakawhetai ki te wāhanga hōtaka o te whanaketanga, e kore, i te mohio etahi whanuitanga cybernetics, engari i roto i te tahi atu wāhanga o te pūtaiao rorohiko haere tonu ta'uma. timata matou ki te tini me te whakawhanake reo papatono, e hāngai ana i runga i te wetereo o 26 pukapuka o te pū, me te huinga o te tahi atu tohu noa.

Ko te kuware, me te taiao tino ko te waehere whenua, ko reira tino, tino, engari he motuhake ki ia hoahoanga, me reo taumata-tiketike whakaaro o te mateā puta noa architectures tonu ka akiaki. Tenei nui contradicts te kau o nāianei: te papa whenua hoki orotahi JavaScript typeof = kāore | aho | tau | Pūreana | whakahe | mahi, ki te kahore i reira ohie. i tino ōkawa reo katoa, E te wetereo tino, me te karo papû ore.

Types, taurangi, me o ratou whakamahinga

Ko te tino nui Point. Patopato me whakaahuatanga o te taurangi - te wāhanga tino nui o te hōtaka, e kore e taea e te kaihātepe tuhituhi i te hātepe mahi, i te kore whakatau i te tino kanorau o te raraunga i roto i te pikitia ōkawa tino o taurangi, huānga, ngā me mahi.

faaite JavaScript putu mo tekau tau katoa o te kaha mahi, ana whakaaro katoa maitai whakaata i te māramatanga o nāianei o te wetereo, me ture tika whakatakotoria i roto i tona semantics.

Ko te pātai, ko te, ka kia kia meatia tenei i te mea e tika ana ki te tautuhi i te kuputuhi momo, JavaScript typeof mahi. Mau patopato kuputuhi te iti kōwhiringa hoa: te aho pūāhua me te tau. Heoi, ko te tūranga o te ahanoa kuputuhi e taea te tākaro, me te ara ngohi o array.join hoahoa (), e hono nga mea timatanga katoa ki te kuputuhi kotahi, e ko, i roto i te raina kotahi.

tauākī banal: katoa a tawhio noa i reira he momo kuputuhi, a JavaScript kia typeof mahi i te wa e tika ki te mahi i te whakamāramatanga momo e hiahiatia ana. Ko te pono tenei, engari i roto i te mahi huri i te reira i roto i te kore. ka hoatu e JavaScript ahanoa typeof te uara taua i roto i te wā e toru katoa:

aaa = {}; var keee = {};
= typeof ( aaa ); Res = typeof (keee);
+= '/' + typeof window . Res + = '/' + typeof matapihi. ; tuhinga;
+= '/' + typeof ( document . forms [ 0 ]); Res + = '/' + typeof (tuhinga puka [ 0]).

hua: ahanoa / ahanoa / ahanoa

Mā te taea te typeof (keee) me hōputu typeof keee waiata - e kore e mea faufaa, engari i roto i te wā katoa i homai te whakahoki te, engari reira e kore tino te auraa tetahi!

riro te papu ore tino

Papatono āhuatanga o akiakinga i rawe ki: Kei te rere i te reira na nohopuku mua e te whakawhānui tonu tauine nekehanga. Ko te pūkete haere i runga i mo nga marama, wiki ranei ra, ētahi wā noa haora. Ko nga mahi motuhake o te akiakinga o te hanganga o te hātepe papatono mō te whakaoti taua he nohopuku-vitiviti me tono i runga i te tonu e taea te kaihātepe mahi i te āhua o te whakakahore te whakatau mo te ra, te wiki roa ranei.

otinga Natural JavaScript typeof me mahi o te hōtaka ahanoa-hāngai, i roto i tenei wetereo ko ahua rerekē i meatia i roto i te reo hou pātata nei, te hünuku te pokapū o te mahara i runga i te ahanoa. wāhi Tino salient: riro te reo he mea hangä ngā semantics, nui atu i te huinga o ngā ture syntactic.

e kore e hiahia ana ngā momo raraunga Simple ki te whakatau i tona momo, kaua te whakamahi o JavaScript typeof nui ranei. Ki te tika, e te wāhaere tiaki o nga panoni tika, engari mo te JavaScript typeof ahanoa homai te whakahoki tino whaitake ko te ahanoa me te momo o te raruraru - i tona āwangawanga! Tenei arorau hoki te whakaaro puāwaitanga e pā ana ki papatono uaua ki rangona, engari reira ko te āhua tūturu o nga mea tika.

Tiaki wāhi - ki te whakatau i tona momo, ki te whakaatu o ratou āhuatanga, me te mahia o ratou tikanga. Papatonotanga ki whakakanapatia koutou wetereo, me te kau katoa o te wā te hünuku te pokapū o te mahara o te wetereo i hanga e semantics kaihātepe: tona pūnaha o ngā e mahi i te mahi.