Dambudziko guru rekuyera basa rekumhanya nguva nderekuti zvinogona kunetsa kuona kuti rimwe basa rinotora nguva yakareba sei kuita. Izvi zvinodaro nekuti nguva inotora kuti basa rishande rinogona kuenderana nezvinhu zvakasiyana siyana, zvinosanganisira kukura nekuoma kwechishandiso chacho, komputa yachiri kuisirwa, uye kumhanya kweprosesa yekombuta.
There are many ways to measure the run time of a function in JavaScript. One way is to use the Date object:
function measureFunctionRunTime(func) { var start = new Date().getTime(); func(); var end = new Date().getTime(); return end - start; }
1. Basa iri rinotora parameter inonzi "func" inova basa.
2. Inobva yagadzira chinhu chitsva cheDate uye inowana nguva mumamilliseconds (getTime()). Ino ndiyo nguva yekutanga.
3. Inobva yaita basa rakapfuudzwa separameter.
4. Inogadzira chimwe chinhu chitsva cheDate uye inowana nguva zvakare mumamilliseconds (getTime()). Ino ndiyo nguva yekupedzisira.
5. Pakupedzisira, inodzorera musiyano pakati penguva yekupedzisira uye nguva yekutanga (kuguma - kutanga). Izvi zvinokupa iwe nguva yekumhanya yebasa mumamilliseconds.
Union Types
Kune mhando nhatu dzemibatanidzwa muJavaScript: yakasimba, yakasununguka, uye isina kujeka.
Mibatanidzwa yakasimba ndiyo inonyanyoganhurira. Vanobvumira chete rudzi rwechimwe chinhu kubatanidzwa neimwe mhando yechinhu. Semuyenzaniso, mubatanidzwa wakasimba pakati penhamba netambo waizongobvumira kuti nhamba dzose dzibatanidzwe netambo. Mibatanidzwa yakasununguka haina kuganhurira pane mibatanidzwa yakasimba. Vanobvumira chero mhando mbiri dzezvinhu kuti dzibatanidzwe, chero bedzi musanganiswa une musoro. Semuenzaniso, mubatanidzwa wakasununguka pakati penhamba netambo unogonawo kusanganisira nhamba nezviratidzo. Mibatanidzwa yemubatanidzwa ndiyo mhando yemubatanidzwa isinganyanyi kuganhurira. Vanobvumira chero mhando yechinhu kuti ibatanidzwe nechero imwe mhando yechinhu, pasina kudoma kuti imhando ipi yemubatanidzwa. Semuyenzaniso, mubatanidzwa wakajeka pakati penhamba netambo unogonawo kusanganisira nhamba nezviratidzo.
Typing
Kutaipa muJavaScript kwakasiyana zvishoma pane kutaipa mune mimwe mitauro. MuJavaScript, haufanire kunyora iro rakazara kiyi kana zita rebasa. Iwe unogona kungonyora tsamba yekutanga yeiyi kiyi kana basa uye iro rose rezwi rinozopedzwa otomatiki.
Semuyenzaniso, kana waida kutaipa “function”, waingonyora “f” uye JavaScript yaizopedzisa rimwe rasara reizwi rako. Kana iwe waida kunyora "chenjedzo", waingonyora "a" uye JavaScript yaizopedzisa rimwe rasara rezwi rako.
Type Hints
Type hints chinhu chemutauro weJavaScript chinokutendera kuti utaure rudzi rwechirevo pasina kushandisa typeof operator. Semuenzaniso, iyo inotevera kodhi inozivisa kuti shanduko x inhamba:
var x = 5;
Iwe unogona zvakare kushandisa mazano emhando paunenge uchitsanangura basa. Semuenzaniso, iyo inotevera kodhi inozivisa basa rinotora yekuisa parameter yemhando nhamba uye inodzosera tambo:
wedzera basa (x) {kudzoka x * x; }
