React初心者がHooksを理解するためにコードを読んでみた

Transcript

1. !QPMJEPH 3FBDUॳ৺ऀ͕)PPLTΛཧղ͢ ΔͨΊʹίʔυΛಡΜͰΈͨ 4IJ[VPLBKT
   
   
   

2. ࣗݾ঺հ w !QPMJEPH
   w ύʔςΟʔϋʔυגࣜձࣾ
   w ϑϩϯτΤϯυΤϯδχΞ ݟश͍
   w

   ϲ݄ͪΐͬͱલʹύύʹͳΓ·ͨ͠ 

3. ݁࿦
   3FBDU
   )PPLTͷίʔυ·͡Α͘Θ͔Βͳ͍ʜ

4. ΞδΣϯμ  ͦ΋ͦ΋)PPLTͱ͸ʁ
    3FBDU
   )PPLTͷίʔυΛಡ΋͏ͱࢥ͖͔͚ͬͨͬ
    ࣮ࡍʹίʔυΛಡΜͰΈͨ

5. ͦ΋ͦ΋3FBDU
   )PPLTͱ͸ʁ

6. 3FBDU
   )PPLTͱ͸ͳʹ͔ʁ w ؔ਺ίϯϙʔωϯτʹεςʔτΛ΋ͨͤΔͨΊͷ࢓૊Έ
   w ؔ৺ࣄΛ୯Ұͷؔ਺ )PPLT ʹ·ͱΊΔ͜ͱ͕ग़དྷΔ
   w Ϋϥείϯϙʔωϯτͩͱॲཧ͕ࢄΒ͹Γ΍͍͢ʁΘ͔Γʹ͍͘ʁ
   ਖ਼௚Ϋϥείϯϙʔωϯτॻ͍ͨ͜ͱͳ͍͔ΒΘ͔Βͳ͍ɻɻɻ

   
   w ػցʹ΋ਓؒʹ΋೉͍͠Β͍͠ UIJT CJOE͋ͨΓͱ͔ʜ
   IUUQTKBSFBDUKTPSHEPDTIPPLTJOUSPIUNMDMBTTFTDPOGVTFCPUIQFPQMFBOENBDIJOFT

7. )PPLTͷछྨ w VTF4UBUF
   
   εςʔτͷ؅ཧ
   w VTF&⒎FDU
   
   ෭࡞༻ΛҾ͖ى͜͢ɺYYYͷ஋͕มߋ͞Εͨ৔߹ʹͳʹ͔ॲཧΛ ͤ͞ΔΈ͍ͨͳͷ͕Ͱ͖Δ
   w VTF$BMMCBDL
   
   ίʔϧόοΫͷϝϞԽ ৄ͘͠͸ެࣜυΩϡϝϯτಡΜͰ͍ͩ͘͞
   IUUQTKBSFBDUKTPSHEPDTIPPLTSFGFSFODFIUNM

8. None

9. ίϯϙʔωϯτ͔ΒϩδοΫΛ෼཭ͨ͠ྫ

10. 3FBDU
    )PPLTͷίʔυΛಡ΋͏ ͱࢥ͖͔͚ͬͨͬ

11. w Χ΢ϯτΞοϓϘλϯ͕ԡ͞ΕΔͨ ͼʹදࣔ͞ΕΔ DPOTPMFMPH bSFOEFS` ͕࣮ߦ͞ΕΔ w ͔͠͠DPVOUͷ஋͸ͲΜͲΜ Ճࢉ͞Ε͍ͯ͘

12. ͲΜͳ࢓૊Έʹͳ͍ͬͯΔͷ͔
    ؾʹͳΔ

13. ࣮ࡍʹίʔυΛಡΜͰΈͨ

14. Ͳ͔͜ΒಡΉ͔ʁ w ӈͷΑ͏ͳΧ΢ϯτΞοϓ͢Δ αϯϓϧίʔυΛ૝ఆ
    w VTF4UBUFͷ࣮૷͕Ͳ͏ͳ͍ͬͯ Δͷ͔Λ֬ೝͯ͠ΈΔ

15. ࠓΘ͔͍ͬͯΔ͜ͱ VTF4UBUFͷܕ৘ใ͔ΒΘ͔Δ͜ͱ

16. VTF4UBUFͷؔ਺ͷ࣮૷͸Ͳ͜ʹ͋Δͷ͔ʁ QBDLBHFTSFBDUTSD3FBDU)PPLTKT IUUQTHJUJP+-Q%

17. 3FBDU)PPLTKT
    SFTPMWF%JTQBUDIFS IUUQTHJUJP+-I:

18. 3FBDU$VSSFOU%JTQBUDIFS SFBDUQBDLBHFTSFBDUTSD3FBDU$VSSFOU%JTQBUDIFSKT IUUQTHJUJP+-OW+

19. 3FBDU*OUFSOBM5ZQFTKT IUUQTHJUJP+-OUB

20. ͜͜·ͰͰཧղͰ͖ͨ͜ͱ w VTF4UBUFؔ਺͸EJTQBUDIFSʹॲཧΛҕৡ͍ͯ͠Δ͚ͩ
    w EJTQBUDIFS͸3FBDU$VSSFOU%JTQBUDIFSDVSSFOUͷ΋ͷ͕࢖ΘΕ͍ͯΔ

21. 3FBDU$VSSFOU%JTQBUDIFSDVSSFOU͸ Ͳ͜Ͱ஋͕ઃఆ͞Ε͍ͯΔͷ͔ʁ

22. 3FBDU$VSSFOU%JTQBUDIFSDVSSFOUͰݕࡧͯ͠Έͨ

23. ͦͯͨ͠ͲΓண͍ͨ3FBDU'JCFS)PPLTOFXKT

24. ͓ͦΒ͘͜͜Ͱ%JTQBUDIFS͕ઃఆ͞Ε͍ͯΔ SFOEFS8JUI)PPLT ؔ਺ IUUQTHJUJP+-MD

25. )PPLT%JTQBUDIFS0O.PVOUΛݟͯΈΔ

26. )PPLT%JTQBUDIFS0O6QEBUFΛݟͯΈΔ IUUQTHJUJP+-#WP

27. ͜͜·ͰͰཧղͰ͖ͨ͜ͱ w EJTQBUDIFS͸͓ͦΒ͘)PPLT%JTQBUDIFS0O.PVOU
    PS
    )PPLT%JTQBUDIFS0O6QEBUFΛ࢖༻͢Δ
    w VTF4UBUFͷ࣮ଶ͸NPVOU4UBUF
    PS
    VQEBUF4UBUF

28. ਖ਼͍͔֬͠ೝ͢ΔͨΊʹ
    εςοϓ࣮ߦͯ͠ΈΑ͏

29. None
30. None

31. ͜͜·ͰͰ֬ೝͰ͖ͨ͜ͱ w ॳճͷඳը࣌ͷVTF4UBUF͸NPVOU4UBUF
    w ࠶ඳըͷ৔߹͸VTF4UBUF͸VQEBUF4UBUF

32. NPVOU4UBUF͸ͳʹΛ͍ͯ͠Δͷ͔ʁ IUUQTHJUJP+-MD

33. NPVOU4UBUFͱ͸ͳʹ͔ʁ w )PPLͰঢ়ଶ؅ཧ͍ͯ͠ΔΆ͍
    w EJTQBUDI"DUJPOͷͳ͔ͰԿ͔͠Β஋Λߋ৽͢Δ࢓૊ΈΛ΋͍ͬͯΔ
    w ࣮ࡍͷ஋Λม͑Δͷ͸RVFVFͷ෦෼ʁ

34. EJTQBUDI"DUJPOΛݟͯΈΑ͏

35. Α͘Θ͔Βͳ͍͗͢͞Δɾɾɾ

36. ͱΓ͋͑ͣVQEBUF4UBUFΈͯΈΕ ͹ͳΜ͔Θ͔Δ͔΋ʁ

37. VQEBUF4UBUF͸࣮ଶ͸VQEBUF3FEVDFSΛίʔϧͯ͠Δ͚ͩ

38. VQEBUF3FEVDFS·͡Θ͔ΒΜʜ

39. ίʔυಡΜ͚ͩͩ͡Ό
    Θ͔Βͳ͍ɾɾɾ

40. VQEBUF4UBUFͱEJTQBUDI"DUJPO ͷؔ܎ੑΛߟ͑ͯΈΔ

41. Χ΢ϯτΞοϓϘλϯ ͕ԡ͞ΕΔ %JTQBUDIFS͕࣮ߦ͞Ε Δ VQEBUF4UBUF͕࣮ߦ͞ ΕΔ

42. %JTQBUDI"DUJPOͷίʔυൈਮ

43. VQEBUF3FEVDFSͰ஋Λߋ৽͍ͯ͠ΔΆ͍Օॴ VQEBUFม਺ͷ࣮ଶ͸͓ͦΒ͘%JTQBUDI"DUJPOͰઃఆͨ͠RVFVF

44. ͳΜͱͳ͘ཧղͨ͜͠ͱ w %JTQBUDI"DUJPOͰRVFVFʹ৽ͨͳ஋Ληοτ͢Δ
    w VQEBUF3FEVDFSଆͰͦͷRVFVFΛड͚औΓ஋ΛมԽͤ͞Δ

45. ·ͩཧղͷղ૾౓͕௿͍ʜ

46. ݶքΛײͨ͡ͷͰNJ[DIJେઌੜͷ ຋༁هࣄΛಡΜͰݟΔ IUUQTHJTUHJUIVCDPNNJ[DIJGBEGDEGCDBCDCEEE

47. ࠷ॳ͔Β͜ͷهࣄಡΜͰ͓͚͹Α ͔ͨͬͨʜ

48. ·ͱΊ w VTF4UBUF͸NPVOU4UBUF΍VQEBUF4UBUFͳͲঢ়گʹԠ࣮ͯ͡ࡍʹ࣮ߦ͢Δؔ ਺͕ҧ͏
    w %JTQBUDI"DUJPO͔Βઌ͸3FBDUΛશମతʹ͋Δఔ౓ཧղͯ͠ͳ͍ͱίʔυΛ ಡΈղ͘ͷ͸ݫͦ͠͏
    w ͔ͯಡΉඞཁ͋Δͷ͔ʁ
    w

    ͍͔ͭϦϕϯδ͍ͨ͠ʜ

49. ͝ਗ਼ௌ͋Γ͕ͱ͏͍͟͝·ͨ͠ɻ