Video: Cov lus cog tseg ua haujlwm li cas JavaScript?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Ua Peb Tus Kheej JavaScript Promises
Cov cog lus constructor siv lub luag haujlwm (tus executor) uas yuav raug tua tam sim ntawd thiab dhau mus rau ob txoj haujlwm: daws, uas yuav tsum raug hu thaum lub cog lus raug daws (dhau ib qho txiaj ntsig), thiab tsis lees paub, thaum nws tsis lees paub (dhau qhov yuam kev).
Xav txog qhov no, cov lus cog tseg hauv JavaScript yog dab tsi?
JavaScript | Kev cog lus . Kev cog lus yog siv los tswj cov haujlwm asynchronous hauv JavaScript . Lawv yooj yim los tswj thaum cuam tshuam nrog ntau yam haujlwm asynchronous qhov twg callbacks tuaj yeem tsim kev hu rov qab ntuj raug txim ua rau tsis muaj cai tswj tau.
Tsis tas li ntawd, vim li cas peb thiaj xav tau cov lus cog tseg hauv JavaScript? Cov lus cog tseg cia ua yuam kev dhau los ntawm cov saw hlau thiab ua haujlwm hauv ib qho chaw uas tsis tas yuav tsum tau muab tso rau hauv cov txheej txheem ntawm kev tuav yuam kev. cog lus cov khoom siv los ua haujlwm asynchronous. Los ntawm kab thib 1 ntawm MDN cov ntaub ntawv: Cov cog lus khoom yog siv rau asynchronous xam.
cov lus cog tseg ua haujlwm li cas hauv qab lub hood?
Kev cog lus , hauv qab hood . Koj tab tom hla kev hu xov tooj rov qab uas txhais cov cwj pwm tshwj xeeb ntawm koj cog lus . A cog lus yog lub thawv uas muab API rau peb tswj thiab hloov pauv tus nqi, thiab nws qhov tshwj xeeb yog tias nws cia peb tswj hwm thiab hloov cov txiaj ntsig uas yeej tsis tau muaj.
Puas yog JavaScript cog lus asynchronous?
Kev cog lus muab lwm txoj hauv kev yooj yim rau kev ua, sau thiab tswj asynchronous kev ua haujlwm thaum piv rau cov txheej txheem hu rov qab raws li kev cai. Lawv kuj tso cai rau koj lis asynchronous yuam kev siv txoj hauv kev uas zoo ib yam li synchronous sim / ntes.
Pom zoo:
Cov lus cog tseg hauv cov ntawv sau yog dab tsi?
Cov lus cog tseg yog ib yam khoom TypeScript uas yog siv los sau cov kev pabcuam asynchronous. Kev cog lus ib txwm yog qhov kev xaiv zoo dua thaum nws los tswj ntau yam haujlwm asynchronous, kev ua yuam kev thiab kev nyeem cov lej zoo dua
Cov lus cog tseg hauv AngularJS yog dab tsi?
Kev cog lus yog ib yam khoom uas rov qab los ntawm Deferred object. Koj tuaj yeem sau npe sib txawv callbacks rau cov xwm txheej sib txawv daws(), tsis lees paub(), lossis ceeb toom() thiab nws yuav ua tiav thaum lub async ua tiav. Deferred API: Ib qho piv txwv tshiab ntawm defer yog tsim los ntawm kev hu $q
Puas muaj ib txoj hauv kev pov tseg qhov kev kuaj xyuas los ntawm txoj kev uas tsis muaj cov lus pov tseg?
9 Teb. Koj tuaj yeem pov cov kev txwv tsis raug txheeb xyuas yam tsis tas yuav tshaj tawm lawv yog tias koj xav tau tiag tiag. Unchecked kev zam txuas ntxiv RuntimeException. Throwables uas txuas ntxiv yuam kev tseem tsis tau txheeb xyuas, tab sis tsuas yog yuav tsum tau siv rau cov teeb meem loj tiag tiag (xws li invalid bytecode)
Cov lus cog tseg ua haujlwm li cas hauv JavaScript?
Ua Peb Tus Kheej JavaScript Promises Cov Lus Cog Tseg yuav siv lub luag haujlwm (tus neeg ua haujlwm) uas yuav tsum tau ua tam sim ntawd thiab dhau los ntawm ob txoj haujlwm: daws, uas yuav tsum raug hu thaum Cov Lus Cog Tseg raug daws (dhau qhov tshwm sim), thiab tsis lees paub, thaum nws tsis lees paub. (dhau qhov yuam kev)
Dab tsi yog cov lus cog tseg hauv AngularJS?
Kev cog lus yog ib yam khoom uas rov qab los ntawm Deferred object. Koj tuaj yeem sau npe sib txawv callbacks rau cov xwm txheej sib txawv daws(), tsis lees paub(), lossis ceeb toom() thiab nws yuav ua tiav thaum lub async ua tiav. Deferred API: Ib qho piv txwv tshiab ntawm defer yog tsim los ntawm kev hu $q