Rx分からんを解消する会

社内勉強会での資料です。
RxSwiftについて開発メンバーから寄せられた質問に対して答える感じで用意した資料となります。

1. Komerco Div 2018.10.22(MON) Rx෼͔ΒΜΛղফ͢Δձ 3Y෼͔ΒΜΛղফ͢Δձ 4VHVSV
   ,JTIJNPUP
2. Cookpad Inc. All Rights Reserved. ࣄͷൃ୺
3. Cookpad Inc. All Rights Reserved.
4. Cookpad Inc. All Rights Reserved.
5. Cookpad Inc. All Rights Reserved. ͻͬͦΓ΍Δͭ΋Γ͕
   ѹ
   ͕͔͔ͬͨͷͰ
   ษڧձܗࣜͰ΍Δ͜ͱʹ
6. Cookpad Inc. All Rights Reserved. ⚠ॾ஫ҙ⚠ wدͤΒΕ࣭ͨ໰Λݩʹࢿྉ࡞ͬͯ·͢
   wޙ൒͸ࣗ༝࣌ؒʹ͢ΔͷͰΘ͍Θ͍ٞ࿦ͨ͠Γ͠·͠ΐ͏
7. Cookpad Inc. All Rights Reserved. ૣ଎
8. ʲQ1ʳ Observable,Observer,Subject,Relay,Signal,Driver… ͦΕͧΕͷ໾ׂͱ͔࢖͍ಓ͸?
9. Cookpad Inc. All Rights Reserved. 0CTFSWBCMF0CTFSWFS w0CTFSWBCMF
   σʔλιʔεɺετϦʔϜͱ͔ݺ͹ΕΔɻ஋͕ྲྀΕͯ ΔɺA؍ଌͰ͖Δ΋ͷAɻ
 ஋͕ྲྀΕͯ͘Δͱɺࣗ৴ʹొ࿥͞Εͨ0CTFSWFSʹ஋Λ௨஌͢Δ
 w0CTFSWFS
   A؍ଌ͢Δ΋ͷAɻ0CTFSWBCMFͰྲྀΕ͍ͯΔ஋Λड͚औ ΔͨΊʹɺ0CTFSWBCMFʹࣗ਎Λొ࿥ͨ͠ΓɺෆཁʹͳͬͨΒղআ ͨ͠Γ͢Δ
10. Cookpad Inc. All Rights Reserved. Ҿ༻
    IUUQTRJJUBDPN.BTBOPCV"LJCBJUFNTBCEDDFF
11. Cookpad Inc. All Rights Reserved. 0CTFSWBCMF0CTFSWFS w0CTFSWBCMF 5ZQF Ͱ͋Δ΋ͷ
 A0CTFSWBCMF&A
    A4JOHMF&A
    A.BZCF&A
    A$PNQMFUBCMFA
    A̋̋4VCKFDU&A
    A̋̋3FMBZ&A
 ݫີʹ͸ҧ͏͚ͲɺA%SJWFS&A
    A4JHOBM&A΋
    w0CTFSWFS 5ZQF Ͱ͋Δ΋ͷ
    
 A̋̋4VCKFDU&A
    
    A"OZ0CTFSWFS&A
    A"OPOZNPVT0CTFSWFS&A
12. Cookpad Inc. All Rights Reserved. 0CTFSWBCMF0CTFSWFS w0CTFSWFS 5ZQF গͳ͘ͳ͍ʁͦͯ͋͠·Γఆٛ͢Δ͜ͱͳ͍Μ͚ͩ Ͳʜ
 
 ˠීஈ
    ATVCTDSJCF PO/FYUPO&SSPS A
    ͱ͔ͰΫϩʔδϟ౉͍ͯ͠Δ ͷͰࣗ਎Ͱ0CTFSWFSΛੜ੒͢Δ͜ͱ͸গͳ͍͕ɺཪͰ͸࡞ΒΕͯ ͍Δ
13. Cookpad Inc. All Rights Reserved.
14. Cookpad Inc. All Rights Reserved.
15. Cookpad Inc. All Rights Reserved. 4VCKFDU3FMBZ w4VCKFDU
    0CTFSWBCMF5ZQF
    
    0CTFSWFS5ZQF
 ࣗ਎Ͱ஋Λྲྀ͢͜ͱ΋Ͱ͖Δ͠ɺ0CTFSWBCMFʹొ࿥ͯ͠஋Λड͚ औΔ͜ͱ΋Ͱ͖Δ
    w1VCMJTI4VCKFDUɺ#FIBWJPS4VCKFDUɺ3FQMBZ4VCKFDU͕͋Δ
    w7BSJBCMF
    ˠ
    3Y4XJGU
    W͔Βඇਪ঑
16. Cookpad Inc. All Rights Reserved. 4VCKFDU3FMBZ w3FMBZ
    4VCKFDUͷϥούʔ
    w&SSPS
    $PNQMFUFE͕ྲྀΕͯ͜ͳ͍
    w1VCMJTI3FMBZ͸1VCMJTI4VCKFDUɺ#FIBWJPS3FMBZ͸#FIBWJPS4VCKFDU ͷϥούʔʹͳ͍ͬͯΔ
    w&SSPS
    $PNQMFUFE͕ྲྀΕͳ͍ͷͰɺ
 
    1VCMJTI3FMBZˠ4JHOBM
 
    #FIBWJPS3FMBZˠ%SJWFS
 ʹ؆୯ʹม׵Ͱ͖Δ
17. Cookpad Inc. All Rights Reserved. 4JOHMF.BZCF$PNQMFUBCMF w3Y4XJGU
    W͔Β౥ࡌ͞Εͨɺ0CTFSWBCMF&ͷᙱ͍ͱ͜ΖΛγʔϯ ผʹղܾͯ͘͠ΕΔ΋ͷɻͦΕͧΕFWFOU͸
    ճ
    ͔͠ྲྀΕͳ͍
    w
    ඞͣ&SSPS͔$PNQMFUFEͷͲͪΒ͔ͰऴΘΔ
    w/FYUͷྲྀΕΔճ਺͕ҧ͏
    w4JOHMF
    ճ
    w.BZCF
    ճ΋͘͠͸ճ ྲྀΕͣʹ$PNQMFUFE͚ͩྲྀΕΔ͜ͱ͕͋Δ
    w$PNQMFUBCMF
    ճ
18. Cookpad Inc. All Rights Reserved. %SJWFS4JHOBM w&SSPS͕ྲྀΕͳ͍
    wϝΠϯεϨουͰ࣮ߦ͞ΕΔ͜ͱ͕อূ͞Ε͍ͯΔ
    w%SJWFS͸4VCTDSJCFͨ࣌͠ʹ௚ۙͷ஋Λճྲྀ͢ ASFQMBZ  A
    w4JHOBM͸4VCTDSJCF͔ͯ͠ΒྲྀΕͯ͘Δ
    w6*ʹབྷΉ෦෼Ͱ࢖͏ͷʹ΋͍ͬͯ͜
    w1SFTFOUFSˠ7JFXɺ7JFX.PEFMˠ7JFXͰΑ͘࢖͏
19. Cookpad Inc. All Rights Reserved. ࢀߟ w3Y$PDPB
    
    ͷ
    4JHOBM
    ͱ
    3FMBZ
    ͷ·ͱΊ
    wIUUQTUFDINFSDBSJDPNFOUSZ
    w3Y4XJGU
    ͷ༻ޠ·ͱΊ
    wIUUQTRJJUBDPNNPSJTIJOJUFNTDEFCGF
    w3Y4XJGU
    ͷ
    0CTFSWBCMF
    ͱ͸Կ͔
    wIUUQTRJJUBDPNHPNJ@OJOHFOJUFNTDDGFCFFDG
    w3Y4XJGU
    Λ΍ΔલʹͪΌΜͱ
    0CTFSWFS
    ύλʔϯΛֶͿ
    wIUUQTTUBSIPTIJIBUFOBCMPHDPNFOUSZ 394XJGU@&&&#&%&"#&"&& &"@0CTFSWFS@&&#'&#$&#&&"%" &#
20. ʲQ2ʳ `subscribe`, `bind`, `drive`, `emit` ͷ࢖͍෼͚͸?
21. Cookpad Inc. All Rights Reserved. ͲΕ΋ߪಡ͢Δ࣌ʹ࢖͏΋ͷ͚ͩͲ
    ඍົʹੑ࣭͕ҟͳΔ
22. Cookpad Inc. All Rights Reserved. ATVCTDSJCF PO/FYU
    ʜ A wOFYU
    FSSPS
    DPNQMFUFE
    TVCTDSJCFE
    EJTQPTFEɺͦΕͧΕड͚औͬ ͨͱ͖ͷॲཧΛهड़Ͱ͖Δ
    w4JOHMF .BZCF $PNQMFUBCMFʹͳΔͱड͚औΕΔ΋ͷ͕มΘΔ
23. Cookpad Inc. All Rights Reserved. ACJOE UP A wྲྀΕΛଞͷετϦʔϜʹͭͳ͛Δ࣌ʹ࢖͏
    wҾ਺ʹ͸0CTFSWFS5ZQF΋͘͠͸3FMBZ͕ೖΔ
 ͕ɺϨγʔόͷ0CTFSWBCMF5ZQFʹΑͬͯएׯมΘΔ
24. Cookpad Inc. All Rights Reserved. ACJOE PO/FYU A wOFYUΛड͚औͬͨͱ͖ͷॲཧΛهड़Ͱ͖Δ
 ATVCTDSJCF PO/FYU A
    ͷΈͷ7FS
    ͩͱࢥ͑͹ྑ͍
    wFSSPS͕ྲྀΕͯ͜ͳ͍લఏʹͳ͍ͬͯΔͷͰɺ %FCVH؀ڥͰ͸ ྲྀΕ ͯ͘ΔͱΫϥογϡ͢Δ
    w3FMBZΛTVCTDSJCF͢Δͱ͖͸ͬͪ͜Ͱॻ͘΄͏͕ؾ࣋ͪ୹͍ͷͰ γϯϓϧʹॻ͚Δ
25. Cookpad Inc. All Rights Reserved. AESJWF @ A
    AFNJU UP A wACJOE UP Aͷ%SJWFS4JHOBM൛
    wESJWF͸0CTFSWFS5ZQFɺ#FIBWJPS3FMBZͱ
    wFNJU͸0CTFSWFS5ZQFɺ1VCMJTI3FMBZͱ
26. Cookpad Inc. All Rights Reserved. ESJWF
    FNJU
    AYY PO/FYU A wESJWF͸%SJWFSʹରͯ͠ɺFNJU͸4JHOBMʹରͯ͠࢖͏
    wOFYU
    DPNQMFUFE
    EJTQPTFEΛड͚औΕΔ
27. ʲQ3ʳ ΞϓϦͰΑ͘ݟΔ࣮૷ύλʔϯΈ͍ͨͷ͕ ͋Ε͹஌Γ͍ͨͰ͢ɻ - MVVMͰUIͱVMΛόΠϯυ͢Δͱ͖ͱ͔ɻ - WebAPIୟ͍ͯUI·Ͱ൓өͤ͞Δ·ͰͷྲྀΕͱ͔ɻ
28. Cookpad Inc. All Rights Reserved. ύλʔϯΛֶͿͷʹ͓͢͢Ί͸ͪ͜Β
29. Cookpad Inc. All Rights Reserved. w3Y4XJGUͷ&YBNQMF
    wIUUQTHJUIVCDPN3FBDUJWF93Y4XJGUCMPCNBTUFS%PDVNFOUBUJPO &YBNQMFTNE
    w3Y1BHJOBUJPO
    wIUUQTHJUIVCDPNUSZTXJGU3Y1BHJOBUJPO
    w3Y4XJGU
    
    "1*
    SFRVFTU
    
    .77.
    wIUUQTTQFBLFSEFDLDPNTMJHIUBJSSYTXJGUQMVTBQJSFRVFTUQMVTNWWN
30. Cookpad Inc. All Rights Reserved. .77.ͷྫΛऔΔͱʜ w7.ͷJOJUͰWJFXͷΠϕϯτΛ0CTFSWBCMFͱͯ͠౉͢͜ͱ͕ଟ͍
 FH
    ϘλϯͷλοϓɺϦϩʔυͷτϦΨʔʜ
    w"1*ୟ͘ͱ͜Ζ΋3YͰϥοϓͯ͠ετϦʔϜΛ࡞Δ
    w7JFXͷΠϕϯτΛجʹɺ"1*ͷετϦʔϜΛܨ͍Ͱ͋͛ͯɺ݁Ռ΍ ΤϥʔΛ%SJWFS΍4JHOBMΛ࢖ͬͯ౉ͯ͋͛͠Δ
    w7JFXଆͰ஋Λ͙͢ʹࢀর͍ͨ͠ͱ͖͸7.ʹ#FIBWJPS3FMBZΛ༻ҙ ͯ͠ɺASFMBZWBMVFA
    Ͱࢀর͢Δ
31. ʲQ4ʳ ΩϨΠʹετϦʔϜΛ࡞Δʹ͸?
32. Cookpad Inc. All Rights Reserved. ΩϨΠͳετϦʔϜΛ૊Ήʹ͸ɺ
    ετϦʔϜʹखΛՃ͑ΔΦϖϨʔλʔΛ
    ཧղ͢Δඞཁ͕͋Δ
33. Cookpad Inc. All Rights Reserved. KVTU
    FSSPS
    FNQUZ
    OFWFS
    DSFBUF
    PG
    EFGFS
    
    GJMUFS
    NBQ
    [JQ
    DPNCJOF-BUFTU
    XJUI-BUFTU'SPN
    DPODBU
    NFSHF
    GMBU.BQ
    GMBU.BQ-BUFTU
    GMBU.BQ'JSTU
    UBLF
    TLJQ
    SFUSZ
    BNC
    DBUDI
    TXJUDI
    UISPUUMF
    EFCPVODF
    UJNFPVU
    CVGGFS
    XJOEPX
    ʜ ˞ݴޠʹΑͬͯඍົʹΦϖϨʔλʔ໊͕ҟͳͬͨΓ͢Δ৔߹͋Γ
34. Cookpad Inc. All Rights Reserved. Ұ౓ʹ֮͑Δͷ͸େม
    গͣͭ͠ಈ࡞Λཧղ͠ͳ͕ΒਂΊ͍ͯ͘
35. Cookpad Inc. All Rights Reserved. ʮͲ͔͜ʹ·ͱ·ͬͯͳ͍ͷʁʯ
36. Cookpad Inc. All Rights Reserved. 0QFSBUPSΛֶͿ w3FBDUJWF9
    
    0QFSBUPST
    wIUUQSFBDUJWFYJPEPDVNFOUBUJPOPQFSBUPSTIUNM
    w3Y.BSCMFT 3Y+4
    wIUUQSYNBSCMFTDPN
    w3Y.BSCMFTͷJ04
    "QQ΋͋Δ
37. Cookpad Inc. All Rights Reserved.
38. Cookpad Inc. All Rights Reserved. ʮཧղ͢Δͱදݱͷ෯͕޿͕Δͷ͸ʁʯ
39. Cookpad Inc. All Rights Reserved. KVTU
    FSSPS
    FNQUZ
    OFWFS
    DSFBUF
    PG
    EFGFS
    GJMUFS
    NBQ
    [JQ
    DPNCJOF-BUFTU
    XJUI-BUFTU'SPN
    DPODBU
    NFSHF
    GMBU.BQ
    GMBU.BQ-BUFTU
    GMBU.BQ'JSTU
    UBLF
    TLJQ
    SFUSZ
    BNC
    DBUDI
    TXJUDI
    UISPUUMF
    EFCPVODF
    UJNFPVU
    CVGGFS
    XJOEPX
    ʜ
40. ࠓ͙͢࢖͑ΔςΫχοΫ
41. Cookpad Inc. All Rights Reserved. ͦͷ̍
    AXJUI-BUFTU'SPNA
42. Cookpad Inc. All Rights Reserved.
43. Cookpad Inc. All Rights Reserved. TVCTDSJCFͷதͰTFMGࢀরͯ͠
    ଞͷετϦʔϜͷ஋Λͭͳ͛Δͷ͸ආ͚͍ͨ
44. Cookpad Inc. All Rights Reserved.
45. Cookpad Inc. All Rights Reserved. ετϦʔϜͱɺࢦఆͨ͠ετϦʔϜͷ௚ۙͷ஋Λ
    ͏·ͭ͘ͳ͛Δ͜ͱ͕Ͱ͖Δ
46. Cookpad Inc. All Rights Reserved. ͦͷ
    A[JQA
47. Cookpad Inc. All Rights Reserved.
48. Cookpad Inc. All Rights Reserved. ࠩ෼ΛऔΔͷ͕؆୯ʹͳΔ
49. Cookpad Inc. All Rights Reserved. ͦͷ
    ATDBOA
    ATUBSU8JUIA
50. Cookpad Inc. All Rights Reserved.
51. Cookpad Inc. All Rights Reserved.
52. Cookpad Inc. All Rights Reserved. "1*ͰQBHFࢦఆͯ͠ಡΈࠐΜͰ݁ՌΛ
    ஷΊ͍ͯ͘ͷʹศར
    
53. Cookpad Inc. All Rights Reserved. ͦͷ
    "DUJPO IUUQTHJUIVCDPN3Y4XJGU$PNNVOJUZ"DUJPO
54. Cookpad Inc. All Rights Reserved. "DUJPO w3Y4XJGU$PNNVOJUZͰఏڙ͞Ε͍ͯΔ044
    w*OQVUͱ0VUQVU͕ܾ·ͬͨετϦʔϜͷྲྀΕΛΞΫγϣϯͱͯ͠ఆ ٛ͢Δ
    wͦͷΞΫγϣϯͷ݁Ռ FMFNFOU ɺΤϥʔ FSSPS ɺ࣮ߦத͔Ͳ͏͔ FYDVUJOH ͕ͦΕͧΕετϦʔϜͱͯ͠ఏڙ͞ΕΔ
    w"1*ͷ௨৴΍Կ͔͠ΒͷඇಉظॲཧΛଋͶΔͷʹศར
    wADBUDI&SSPSA AEPAͱA<XFBL
    TFMG>Aͷۤ͠Έ͔Βղ์ͯ͘͠ΕΔ
55. Cookpad Inc. All Rights Reserved.
56. Cookpad Inc. All Rights Reserved. "DUJPOΛ࢖͏ͱ͜͏ͳΔ
57. Cookpad Inc. All Rights Reserved.
58. Cookpad Inc. All Rights Reserved. ͦͷଞ ࿩͔ͨͬͨ͜͠ͱ w)PU$PME
    0CTFSWBCMF
    wTIBSF SFQMBZ
    w4DIFEVMFS
    w#JOEFS
59. Cookpad Inc. All Rights Reserved. ͕ͬͭΓಡΈͳ͕ΒֶͿͳΒ w3Y4XJGU
    3FBDUJWF
    1SPHSBNNJOH
    XJUI
    4XJGU
    wIUUQTTUPSFSBZXFOEFSMJDIDPNQSPEVDUTSYTXJGUSFBDUJWF QSPHSBNNJOHXJUITXJGU