Inkinga enkulu ngokulinganisa isikhathi sokusebenza komsebenzi ukuthi kungaba nzima ukunquma ukuthi umsebenzi othile uthatha isikhathi esingakanani ukuze uqalise. Lokhu kungenxa yokuthi isikhathi esisithathayo ukuze umsebenzi usebenze singancika ezintweni ezihlukahlukene, okuhlanganisa ubukhulu nobunkimbinkimbi bomsebenzi, ikhompuyutha okwenziwa kuyo, kanye nesivinini somprosesa wekhompyutha.
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. Lo msebenzi uthatha ipharamitha ebizwa ngokuthi “func” okuwumsebenzi.
2. Ibese idala into entsha ye-Date futhi ithola isikhathi ngama-millisecond (getTime()). Lesi yisikhathi sokuqala.
3. Ibese isebenzisa umsebenzi ophasiswe njengepharamitha.
4. Idala enye into entsha ye-Date futhi iphinda ithole isikhathi ngama-millisecond (getTime()). Lesi yisikhathi sokuphela.
5. Ekugcineni, ibuyisela umehluko phakathi kwesikhathi sokuphela nesikhathi sokuqala (ukuphela - ukuqala). Lokhu kukunikeza isikhathi sokusebenza somsebenzi ngama-millisecond.
Izinhlobo Zenyunyana
Kunezinhlobo ezintathu zezinyunyana ku-JavaScript: eziqinile, ezixegayo, nezingacacile.
Izinyunyana eziqinile yizona ezivimbela kakhulu. Bavumela uhlobo olulodwa kuphela lwe-elementi ukuthi luhlanganiswe nolunye uhlobo lwe-elementi. Isibonelo, inyunyana eqinile phakathi kwenombolo kanye neyunithi yezinhlamvu izovumela izinombolo eziphelele ukuthi zihlanganiswe neyunithi yezinhlamvu. Izinyunyana ezixegayo azinamkhawulo kunezinyunyana eziqinile. Bavumela noma yiziphi izinhlobo ezimbili zezakhi ukuthi zihlanganiswe, inqobo nje uma inhlanganisela inengqondo. Isibonelo, ukuhlangana okuxekethile phakathi kwenombolo kanye neyunithi yezinhlamvu kungase kuhlanganise izinombolo nezimpawu. Izinyunyana ezingacacile ziwuhlobo lwenyunyana olukhawula kancane. Bavumela noma yiluphi uhlobo lwe-elementi ukuthi luhlanganiswe nanoma yiluphi olunye uhlobo lwe-elementi, ngaphandle kokucacisa ukuthi iluphi uhlobo lwenyunyana. Isibonelo, inyunyana esobala phakathi kwenombolo kanye neyunithi yezinhlamvu ingase ihlanganise izinombolo nezimpawu.
Ukuthayipha
Ukuthayipha nge-JavaScript kuhluke kancane kunokuthayipha ngezinye izilimi. Ku-JavaScript, awudingi ukuthayipha igama elingukhiye eliphelele noma igama lomsebenzi. Ungavele uthayiphe uhlamvu lokuqala lwegama elingukhiye noma umsebenzi bese lonke igama liqedelwa ngokuzenzakalelayo.
Isibonelo, uma ubufuna ukuthayipha “umsebenzi”, ubungavele uthayiphe okuthi “f” bese i-JavaScript izokuqedelela ngokuzenzakalelayo lonke igama. Uma ubufuna ukuthayipha “isixwayiso”, ubungavele uthayiphe u-“a” bese i-JavaScript izokuqedelela ngokuzenzakalelayo lonke igama.
Thayipha Amacebo
Amacebo ohlobo ayisici solimi lwe-JavaScript ekuvumela ukuthi ucacise uhlobo lwesisho ngaphandle kokuthi usebenzise uhlobo luka-opharetha. Isibonelo, ikhodi elandelayo imemezela ukuthi i-variable x iyinombolo:
i-var x = 5;
Ungasebenzisa futhi uhlobo lwamacebo lapho uchaza umsebenzi. Isibonelo, ikhodi elandelayo imemezela umsebenzi othatha ipharamitha yokufaka yohlobo lwenombolo bese ibuyisela iyunithi yezinhlamvu:
umsebenzi wandisa(x) {buyisela x * x; }
