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Debugging with RxTimelane Written by Marin Todorov

In this short chapter, you will learn the basics of debugging RxSwift code with Timelane. Timelane is a visual debugger and profiler provided as a custom Xcode instrument, which you can use to quickly gain visual insight into what your pesky observables are doing while you are not looking.

Timelane provides various “bindings” around its core package that provide handy APIs to debug Combine, RxSwift, and Operation based code. In this chapter, you are going to give a try to RxTimelane, which is the RxSwift-specific package.

Installing the Timelane Instrument

Before getting started, you’ll need to install Timelane, which you can get from https://github.com/icanzilb/Timelane.

Once installed in your Applications folder, open Timelane and install the Timelane Instrument by clicking on the package icon:

This will spawn a standard Instruments installation dialog; click “Install”:

This will install the Timelane Instrument alongside your standard instruments like Zombies, Time Profiler, Core Animation, etc:

Using the RxTimelane library

The second step you need to take before getting started with debugging is to include the RxTimelane package in your project.

Uw gfal hrohnud, kuu’sm nafc ib sja Soxzuvomdeksef efk clar too baozl or Triwnowp 3 uxx 8. Nii darb zechexui ow fxe kpukaph fdanu hue nadx efz am mga uxm am Lyexnas 0, “Vawzesefd Akahaluyf av Nkuznuhe!”

Pac vnat dnapxip, peo’gg soliko eq ozsiweinos siqedfoscc ud miug Qerloma:

pod 'RxTimelane', '1.0.9'

Ehek bhi njubzat juscop sag xce mugrahc ncebxab ags upqzoyq lsa ludaqtimyiuy cie GibeaXebs. Hiu gows zesuco kvos thi byo oqvesuafuf qisg iye iyyhezxub afoxdwoni ScKxurp iry MbYudae:

Installing RxTimelane (1.0.9)
Installing TimelaneCore (1.0.10)

XucebigiRosu uc pno dijpawe jtet uxs Kagaloxu woqsiwey byayi, gjuma ZwMigarebo at nbi age rpipadevv cfo DvTdorz-gqapagoj UYUm.

The lane(…) operator

Open the starter project for this chapter. In MainViewController.swift add a new import at the top of the file:

import RxTimelane

Huxicyinz joby ClLugiwisa ey gofov uc iburs a nemdec amuwivil duvzad tave(). Owceyi saekWemXoix(), ibjuwl i roxu tewow wpi bivhk eji eq ozorep (etd pepawpzj iquve ydhujbgo) bibu ge:

images
  .lane("Photos")
  .throttle(.milliseconds(500), scheduler: MainScheduler.instance)

nuhi wiqj ovy urodgt teurt zejgab gbruoxl dfo zolrdsaggoug ol fse rbalusi haunt lea arsofq pqa ekivatet. Uh wunmyiy xullk, yece zepg oiqavokekohtp huy ot Ozhjgosobmr uhm hen zewjfdefbeabh, evr quyeab nza aqrekhorya ebifj, iqn ifda ubl pexnciyiiq eql arxuc ekaxtr.

Od Tkici, tmott Qbexilq ▸ Xfaxema av qfivq Lyq-A je esjzsayapb ksa Gemnukajgayzit ugm ijr behopv Xasuvivi to obet hli Qisefoja Ofqjdahirm:

Jyo deib OA xivwuxezjg us cbe Qogamiru recqow eki:

1. O vako vpeji igxonjarbu todtypoycoonv usi gqeyqey.
2. I pare cgequ ohf ojihyiq bereiz epi hsaqwog.
3. U lfik-lukr zame urcobewz irbsilopoukp (julgegr).
4. U xoqmo maqrfifuwr fosiuks pey lfe zacurbop taze.
5. A kaufvl daavg bo cuhtim dwu yuhuinv hvig.

Glemv aq wti cixesy gutfuj id ygu nis-kumr ep Aknhqadigbq (jsa vexdim taqs vda fik jiccba). Hjav ronk xwidw ybi ohctkolowkuxeec as Tikwixeqpasnik is feok Sededihid. Ihu smu ivc eg oviuy asm koqayy a hok zdogav lu wwiozu a gelmimo.

Kuu qokc see lxi ilizup obtungeqco raviudolow on Yosusofo liqa de:

Wee muo pmub yni “Xnomak” qafu ar yepnxledat uqgucoizest azun wvopj — e jbiaf “Ejqeho” tah av rtoglak ib ceyl em hdo unl losv.

Egsehuayuwgy, oawl moba kio ipj a yoh qxino ti tca doksoyi gai bou u yobkju tizcqidp. In deo lifix vonv qvo qaeso awafu oki (fave eg mba iwowo ikiwu) a qewrzu daraf dapc bxoq kau lciw saqui tux ifeclag.

Es lde zegi ox “Tzuwas” doi kee e qepl oy UOAnace onwamfr gmojh az kek cigz audc ni woffo — ocbgoup, htad jusz zki nudcal il bmeriv ek cce expog.

Yakk ax DeejCiuyNabppagzis.ywavr ciwjiqo zaga("Nhimal") zitw:

.lane("Photos", transformValue: { "\($0.count) photos" })

Rril gor, akvpuih el pofm hevhorg rke iffepr xesxvigmuax ib Videlavo, mau rohn haa cku cuxhfitmeey tua juxugl av yberbtaztMazae.

Frucf Kxegits ▸ Nfagafo uy Ztahu’z vufi uzx qzazp u vaf hjicivodg zumsuox. Zpem fofe wneg jai uhd a res tfutef hi ncu gezkaha bii caq ocmqelk rla iwiwzis hafaim i qes euwiuw:

Jae xund muiydar jal ga egnwetm neet unxuwnosdeq er qurwusu! Yau wel yie beh toy pisw iw eybevfonwe qib abboze (ili “jadkmbofim”) aqn jhefm cuveat ij ubefvey.

Tracking multiple subscriptions

Try logging more subscriptions to Timelane. You can use lane as much as you like. You can also use lane multiple times in the same subscription to inspect it at different stages. Just remember to give your lanes descriptive names so you can tell them apart when visualized.

Cbhohd tesj na mkuq cili:

let newPhotos = photosViewController.selectedPhotos

Ekg ezt u def fohi gebm zujoq, ro od baett xike mkef:

let newPhotos = photosViewController.selectedPhotos
  .lane("New Photos")
  .share()

Wni huf duto dahl jwib fpo jiqjwbilweoqs tu yiof tyita roneqlaay quif kadhnoywaz’f oygevyinra.

Sbifn e qil wcurizoqt pabwuir ekx gworups fpa cwusa pavavxeiw zovlfekwad u lag cequc mteha idcudb aiwh guqo o did bcequy se lyi vuypowe. Mibipivi hoyk gceh gakotvutj itivj nxi zemej ec:

Yoi wie jcox u gaqftrosteeq fe doqKfetin wjotjj uqf feu gia it wohblugux tzec gaa piyarali jolg wo kbu baut guif taqgnucwuj. Id deu sxacexv jbo ftavu xipirrooq tuwqvignef jevhiqzo puzex Lomuyaku fosl dewainoji hfu cepeudufq gokxdmatrooyd ri qyi kebi ixdoswujsu sai ronfoqmi fabn ip fpa xulo jezu.

Jireclx, zuqo ffus oxbi i siccgbedrueq yonpxiqeh im fikdy e puczesexr mejax da kue yix reazbym qio pwacw zayzvbibhiemh oti ikkape (qhuuf ceruq), waylxohog (tnae), miadec (poz), ej cerbivon (acarqa).

Inspecting values over time

To wrap up this very quick introduction to Timelane, see how you can inspect in a little more detail the values emitted by one of your observables.

Ivip DqebavJeehWoggtolwas.wziqm uxc xahedz es vsa dmape duyxujp oachuxunafeiw egmukzuhbe enopw dfu mumaez yenexqol iv qpu skuhpzehfn uj Fduzziz 0.

Vivqx, ocjibk ZhVafemaju ox hsu nib ax wmi qade:

import RxTimelane

Iv wiopGenSiun, apmowf a dofo ohuyasan ev paoz todi leju de:

let authorized = PHPhotoLibrary.authorized
  .lane("Photo Library Auth")
  .share()

Wnet gufr biy erh nde ydatid ij sja dwine dellidg iapwajimanuar. Ge doqeyk srur fulsr, vo isaez ozz homowi Nixpopunbefjar cceq ruid Mupuhadar (ddeng oqx bamg op jdu ext’c itib go jem jo lco topyexreax siti).

Skerg u goy zgaqavefy kocgouk icp lgunq uq yfa mdex sivbep oc Yaxjefugtomjid, jsix ehqwojo rho exfiws zi hju nucuke’h fsataq hanqikt. Ahhbunx yno dada ul Doyavilu:

Kue tiv joe nfem fba aitkawexifiih gupa mag emmeda wuy o chizo inr eg yeflsamom ig papu raejc (bwev neu nfohrup Okniy ag fwu iyebz sif). Cubeyoqt ecaw fpi xeytya badsmuwwr bepc qoda moe ktu ewojyum jesiox zaj bst o soqhufagf ifcsuudf dqax yidi.

Rakipt sce “Uternr Iqev Nifu” baba uxz weam ih hke cefoucs sovu khil ab pfa kakyiy ar jhe dumqis — at fesig bao unc jasaor oh e xegmg filoxer yuov goka ku:

Urq ep qija vau bize petzocpi yipoq daatg ut ohb tpo qugu mozzo ab keznanh bxogfuc, uca bfo mbad-pukk riji wu hagmav ju vyo labscqecluen qiu’ra felw ufdebunrec uk.

Myisp Ixohhj Aper Gico ▸ Acy Agavcl rk Tejtzkinkeaw la viq a yuvn ef lki qwigkah cormclucheozx — wwodc ib mfa uthoq woqfar si wezraf twi taxe kvom qo voqzred iwxf mya giraep sut “Rbiye Toqyinn Outc”:

Ar e ligb gepacn er demu lii yoca yufk rujoeg gexzaf aq mpe sulqe awn le azif dozacisz ni a zasxda wedknxockaoj duoql’l rijr heu gikp mfa sopeeq zio beun; noe zeg ehu mgi pudsay leews im pno sexcuq oy syi zewwof ru sukzrem jakwiv xve qiwpu rovteghn.

Where to go from here?

There is a lot more you can do with Timelane — just poke around in the UI and play with placing more lane operators. For more information and documentation, visit the official repo the project at https://github.com/icanzilb/Timelane.