Video: Qhov sib piv ua haujlwm hauv JavaScript yog dab tsi?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Lub hom phiaj ntawm cov piv muaj nuj nqi yog los txhais ib qho kev xaiv xaiv. Yog tias qhov tshwm sim zoo b yog txheeb ua ntej a. Yog tias qhov tshwm sim yog 0 tsis muaj kev hloov pauv nrog rau qhov kev txiav txim ntawm ob qhov txiaj ntsig. Piv txwv: Cov piv muaj nuj nqi piv tag nrho cov nqi hauv array, ob qhov nqi ntawm ib lub sijhawm (a, b).
Ua raws li qhov no, koj ua li cas piv cov khoom hauv JavaScript?
Muab piv cov khoom yog ib qho yooj yim, siv === los yog Object.is(). Cov haujlwm no rov qab muaj tseeb yog tias lawv muaj qhov siv tib yam thiab tsis tseeb yog tias lawv tsis ua. Ib zaug ntxiv, cia kuv ntxhov siab, nws yog sib piv cov ntaub ntawv rau cov khoom , tsis yog tus nqi ntawm cov khoom . Yog li, los ntawm Piv txwv 3, Object.is(obj1, obj2); yuav rov cuav.
Tom qab, lo lus nug yog, dab tsi yog localeCompare hauv JavaScript? Txhais thiab siv. Cov localeCompare () txoj kev sib piv ob txoj hlua nyob rau hauv qhov chaw tam sim no. Lub hauv paus yog raws li cov lus teeb tsa ntawm qhov browser. Cov localeCompare () txoj kev xa rov qab tus lej qhia seb txoj hlua tuaj ua ntej, tom qab lossis sib npaug li qhov sib piv String hauv kev txiav txim.
Tsis tas li ntawd, qhov txawv ntawm == thiab === hauv JS yog dab tsi?
= yog siv los muab cov txiaj ntsig rau qhov sib txawv hauv JavaScript . == yog siv rau kev sib piv nruab nrab ob variables tsis hais cov datatype ntawm variable. === yog siv rau kev sib piv nruab nrab ob qhov sib txawv tab sis qhov no yuav txheeb xyuas hom nruj, uas txhais tau tias nws yuav kuaj cov ntaub ntawv thiab sib piv ob qhov tseem ceeb.
Vim li cas peb siv === hauv JavaScript?
Qhov txawv ntawm == thiab === hauv JavaScript Qhov tseeb, koj yuav tsum ib txwm siv " === "tus neeg teb xov tooj rau kev sib piv cov hloov pauv lossis tsuas yog rau kev sib piv xwb. tus neeg teb xov tooj yog tus neeg ua haujlwm nruj tsis muaj vaj huam sib luag, uas yuav siv hom kev txiav txim siab thaum sib piv ob qhov sib txawv lossis ob qhov txiaj ntsig hauv JavaScript.
Pom zoo:
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Dab tsi yog qhov sib txawv tseem ceeb ntawm kev sib txuas lus tsis sib xws thiab kev sib txuas lus taw qhia?
1. Hauv kev sib txuas lus tsis muaj kev sib txuas lus tsis tas yuav tsim kev sib txuas ntawm qhov chaw (sender) thiab qhov chaw (receiver). Tab sis nyob rau hauv kev sib txuas-taw qhia kev sib txuas lus kev sib txuas lus yuav tsum tau tsim ua ntej hloov cov ntaub ntawv