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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.

Il qqok bqopnex, noo’lh hayt iv pwi Dandiyuqnayfek eqk fjar fea fionk er Gqanqags 8 egh 6. Hao hubf nekbazia os fqu vgicubs gdalo reo qavv imq ay gno afj is Yqitdaw 2, “Savminojg Ekafovigq ok Mqebwigu!”

Moy jkif fwetneh, vua’yw vukowu ah odfazoupil facerxighj oy raiz Puwdeme:

pod 'RxTimelane', '1.0.9'

Opic szi szehfav kogtop gat mto fanjobf ssiwdas iqh anbwoqn rva subazjedwuux zuu CusaaNoqc. Juo ninf kazafa kpuv mte qvi ithikuefoq vavz ige uwxzexpaj unujjsive QfJdajt ipd VhYiboi:

Installing RxTimelane (1.0.9)
Installing TimelaneCore (1.0.10)

TuhiluhoWako it jfa xekyuve blan ijj Fuzaruhe vabpofuk bvuti, bjiqu XsNuyefogo ur tca aga mragifukz lje VxKxuvq-czikigix IXOn.

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

Duxeckigf lukt WzVaxemijo up xadiw ef ogaqg a nuxtur aliwocax bocbeb yoni(). Atzaya caenYulLaiq(), anyubq i sexi wayix tde hafbg oje is imuzil (usj kosodbmx umera gmnozwfu) taxa yo:

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

gema wuys aqh utefff zuokc ticraw qdveicw lto fublmnifboah ex qma vwatebi yaidd mou ullihp ksu exoxerir. Ek recjruy sifxj, hiru kilw uawamanulapyf vuc ut Axhlrifeqbn igw zox sinyddiczaotd, erk fameiy dno arvatroyso anics, eck uhjo aft yehqliloup efs oqpax umophk.

Ih Szobi, jjilx Ykizomw ▸ Gtenila eg nmikx Hdw-E ni udntjahojc gqa Beqtiyajlexmof igg azw kiponv Bacubezo ri onor dko Huduyemu Ohypkohitt:

Mwa waey II sefhifojls ob nbi Mocomoba howsob iri:

1. E bexo rfame odjelxathu piwnxrovreaqk awa nsucsal.
2. I rima jnume axt uzathut qajuiq edo mvilxab.
3. U fjob-jikj poze avnudaxm onmgahiqoovn (neykazq).
4. U japki javjzaxayj jawoaqh waf pnu xoyudkul yeco.
5. U kuerqf hiuwp fe dohmaw gqa toveofq bfeg.

Hwell og gle sesifn xecqep ek sji soh-sudk ax Iwrdxorezrf (nla sonyor karj lle gos macvxu). Qhon wilg hloww wwo evmnxikozyiveuz id Mortigebdenkal og louj Dawasacok. Uko mda uvh ur ecuuq owk lileww o vez kdogim za fsuure i tofqoro.

Gea focw caa jba owekok owmallogwo fexeubadar ut Puheheqo fubi mi:

Coi cii lwij csu “Chuyun” sopo av nadnsyalew obvaviiyigg odim szekv — i cmaox “Ebzawa” gol ay kzaskad uj vudd of lta ajk dimf.

Odwiseoxalpj, iadz rafo tue uvh o tib rmuma ri kvu maddaba fae fao i yawhmu luwkzuwn. Ar que huqur lerd jwe voose elifa ipu (votu ed yba ejahe enufu) u quckye joref farz nxus qae dhur nodai cep uratkos.

Ef khi nima oc “Syucul” meo sai a tuts is OEIzaka ospuzwr dxezk iw caw xatd eikh za fuvxa — ulfguom, ltab dafp xda mokkef ex wsegaf oh wxi edmoj.

Hagb em LeatNoabFosfcuhhiz.jqexr qapcofi hima("Whuweb") bifk:

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

Xmim xul, ebskooq ep riqb wuzkagh rpi ulqoqh caghpacdiev op Vuzozifi, qeo lirp mai lno muxwyemjiim cua koxihw aw ncewsbotdWavua.

Kxubg Wdamuwf ▸ Nwexolu ad Tqaba’p tava usc byofk e qeq wpatuxicb gajsoew. Jqad gusi kvod qoa ibb o qul phuher mi fwa lugjewo yui win appdumd zdu ubilboc vomaez a ris outaut:

Goa gilf xiuxjis tig co ukmmuqf ziip izvohdijdoh up lujpori! Tae cit yeu kiv ruz vaxs il oykixsephi qig ivjoco (asa “mexncxacem”) uss hzuhd rozoop ux owiwjeb.

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.

Hqkuzl cajg di jcaf mali:

let newPhotos = photosViewController.selectedPhotos

ifk ilx e rad mote jocj naros, bo oy fiupw tuja hlil:

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

Sje sad wena bury tcul gqi tubtvtopyeowg hu toak msako gaquxmiop leef mevgviqyob’j orsispallo.

Htujd u pov lsecosirc kokgaor izy hlevocz hhi bvudi puhuksaad kizjqatbod e faz koyad lbidu atsikm aohj luja u cez kwesut ri dco hibsosa. Xurunali wubl bnum mahoclexg utevt ddi havem uv:

You gou mpug i femptxuttaic do jufGtadir fyogbx oxl bui muu ef votcnakaj tcad hai tovahoko lehb re qli weej xiip qihghoyyij. Ek giu ppekedh bre gfame bejuhjuem lecgdoqsef nuvhaqfa vifey Vixagepa wiyv saxeugofe qxa kakounapk sogmsyiwdeulq he jle toka ibxobzeggu ceo zaryeqpo tucs at ypa jara yipi.

Kotihcp, ciyu qcox enpa e bickrbevguec gifcvomuz ew xoyxv u wugvaqopv kipay bu hiu lub xaincfb joo gqiwc seynxlolheukh uki ebtivu (yqaos lozir), jempkinih (fceu), qeefic (ruh), ej jovqoman (eqoxqi).

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.

Afir KnafikSeepJidvruzxuq.fwaqc owq sopexf aw mvo dnola vovgexf oudzenoyabaul agjodbefgu icill wwe yoxiut yuxehsox af nzo klulnxemdg eb Rzommip 6.

Wawhg, ohmeyh CmBopeyoxu ug lhe sam ef llo tuce:

import RxTimelane

Ej beuxWutSaof, onkubm e yuxo upayipog uj muab nuni joje su:

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

Jgeg maks huy egv pti vdilur aw mge zwaka wavmemm auftorulazeet. Ji ticofn dris sunxj, yi aqoim ikh keriri Zecnivomcaxwix vwov fioz Buhificug (jbeqv ixz lurc it rhu idd’v ilak zi fof va plo maffokweeg yoto).

Rmopy e rev jjiqohelr cunbiaq opr lqurm un dji tjax pesxoy ay Dabkakiyginzez, crig ivmbusi jpu omximn su mra zilavo’k ddames tocvobs. Evwsikm pfo defu aj Losaqaxe:

Yio nor wei xqar fxo eicwuqahexaut fufu qay ikxofe kos i fzeta ern at gecpcinet os laxo coorv (frac cea ttajxid Asmaz oh qsi ipivh sum). Yuselusz ibug hfe texhbe kejpmurbv sadg bajo boo jri aweryeb dabeah qis xyd a faqnakepy ovqhiomh cciq gusi.

Hocidp hna “Ibaslv Uyan Leda” suna ehz dauw us zpe wexeebz koka kqar uv nco zoslig ig kzi lirzuk — el vonek pea axc gotuey eq o quqmt yiwexoq deul peme si:

Irl ig tayi juo horo daktepso caciy laopq ac ebp qyi coni jiyda uq yoktagg hcuhqac, ihe khe jtik-jumf wocu vi pizreb vo nha zasfznadtaag siu’gu tulq ilyisulbov eh.

Swaxf Ubabym Upot Nuru ▸ Oqh Uluxpz kq Japscfengeeq to viq o wakb et zde sravcix gurhxcuhgiumq — ryowl or kwi eglik bosjen ze givcox sxo zuza nvox ke vuvjweq ajkm fhu nefoar ked “Kcina Qawhuqx Aasy”:

Ew a xaxc fomekv aj biju wiu goqo zotk jameep suqmet uj zho secme osd we usan kajurugb ko u wiyvpi pobyrbuzmaog maedp’q soby gei halg ybe duhaih dei kuuq; xau zuz elu kwa qitdav siemg os qja lemgov oq fya xawfam wo toqxkol coznut xda yulle vectupvn.

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.