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レガシーコードの触り方 / Working Effectively with Legacy Code
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Takuto WADA
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May 13, 2017
Programming
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レガシーコードの触り方 / Working Effectively with Legacy Code
オープンセミナー2017@岡山
Takuto WADA
PRO
May 13, 2017
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Transcript
ϨΨγʔίʔυͷ ৮Γํ ాਓ !U@XBEB .BZ !ΦʔϓϯηϛφʔԬࢁ
ాਓ JEUXBEB !U@XBEB HJUIVCUXBEB
None
ひとり歩きするスタンド ελϯυ໊ϫΠϧυɾαόϯφ
assert(typeof item.id === 'strong') | | | | | |
| false | | "foo" | Item{id:"foo",name:"bar"} "string" --- [string] 'strong' +++ [string] typeof item.id @@ -1,6 +1,6 @@ str -o +i ng https://github.com/power-assert-js/power-assert power-assert
ΑΖ͓͘͠ئ͍͠·͢
ݱ͔ΒͷதܧͰ͢
ർฐ͖ͬͨ͠ݱ
IUUQTXXXqJDLSDPNQIPUPTPLJOBXBTPCB ߥΈ͖ͬͨίʔυ
രॲཧͷΑ͏ͳϦϦʔε
ͭͷlͳΒΘ͠z
IUUQTXXXqJDLSDPNQIPUPTELBMP lςετΛॻ࣌ؒ͘ͳ͍z
ετϨε ςετ
ࣗಈςετ ετϨε
ςετΛॻ͕࣌ؒ͘ͳ͍ͷͰ ͳ͘ɺςετΛॻ͔ͳ͍͔ Β͕࣌ؒͳ͘ͳΔͷͰ͢ɻ
lಈ͘ίʔυʹ৮ΕΔͳz IUUQTXXXqJDLSDPNQIPUPT!/
&EJU1SBZࢮ͕͍ͬͯΔ
$PWFS.PEJGZ
w ʮςετΛॻ͕࣌ؒ͘ͳ͍ʯͷͰ ͳ͘ʮςετΛॻ͔ͳ͍͔Β͕࣌ؒ ͳ͘ͳΔʯ w ʮಈ͘ίʔυʹ৮ΕΔͳʯͱಆ͏ɻ ৮Βͳ͘ͱपΓ͕มΘͬͯಈ͔ͳ ͘ͳΔɻ৮Εͳ͚Είʔυ؇ ͔ʹࢮΜͰ͍͘ ͭͷʮͳΒΘ͠ʯͱಆ͏
ͭͷlಓ͠Δz
w ʮϨΨγʔίʔυͷδϨϯϚʯ w lίʔυΛมߋ͢ΔͨΊʹςετΛඋ͢Δ ඞཁ͕͋Δɻଟ͘ͷ߹ɺςετΛඋ͢Δ ͨΊʹɺίʔυΛมߋ͢Δඞཁ͕͋Δz w ϨΨγʔίʔυʹ৮ΔͨΊͷ ޠኮͱٕ๏Λཧͨ͠ຊ w
TUBDLPWFSqPXDPN͔Βͷ ඃݴٴୈҐ ϨΨγʔίʔυվળΨΠυ
w ϨΨγʔίʔυվળΨΠυΑΓந ͕ߴ͍ w ιϑτΣΞͷϦΤϯδχΞϦϯάΛߦ ͏ͭͷબࢶΛ͍ࣔͯ͠Δ w ϦϑΝΫλϦϯά w ϦΞʔΩςΫςΟϯά
w ϏοάɾϦϥΠτ ϨΨγʔιϑτΣΞվળΨΠυ
Ͳ͜ʹςετΛ ॻ͍͍͔ͯ͘
ʮ௧ΜͩՕॴʯͱʮख͕ಧ͘Ռ࣮ʯ
w ϦεΫ w खಈςετͷίετ w ࣗಈԽίετ ςετͷτϦΞʔδ
ςετέʔεΛҰཡʹ·ͱΊΔ ςετέʔε σβΠϯมߋ ηΩϡϦςΟΞϥʔτ औҾཤྺ ޱ࠲ͷౚ݁ ৽نϢʔβొ ݕࡧ݁Ռͷฒͼସ͑ ͓ۚͷೖۚ ৼΓࠐΈͷ֬ೝ
ϦεΫΛݟੵΔ ςετέʔε ϦεΫ σβΠϯมߋ ηΩϡϦςΟΞϥʔτ औҾཤྺ ޱ࠲ͷౚ݁ ৽نϢʔβొ ݕࡧ݁Ռͷฒͼସ͑ ͓ۚͷೖۚ
ৼΓࠐΈͷ֬ೝ
खಈςετͷίετΛݟੵΔ ςετέʔε ϦεΫ खಈςετͷ ίετ σβΠϯมߋ ηΩϡϦςΟΞϥʔτ औҾཤྺ ޱ࠲ͷౚ݁ ৽نϢʔβొ
ݕࡧ݁Ռͷฒͼସ͑ ͓ۚͷೖۚ ৼΓࠐΈͷ֬ೝ
ࣗಈԽίετΛݟੵΔ ςετέʔε ϦεΫ खಈςετͷ ίετ ࣗಈԽίετ σβΠϯมߋ ηΩϡϦςΟΞϥʔτ औҾཤྺ ޱ࠲ͷౚ݁
৽نϢʔβొ ݕࡧ݁Ռͷฒͼସ͑ ͓ۚͷೖۚ ৼΓࠐΈͷ֬ೝ
༏ઌॱҐΛ͚ͯฒସ͑Δ ςετέʔε ϦεΫ खಈςετͷ ίετ ࣗಈԽίετ ޱ࠲ͷౚ݁ ৼΓࠐΈͷ֬ೝ औҾཤྺ ݕࡧ݁Ռͷฒͼସ͑
͓ۚͷೖۚ ηΩϡϦςΟΞϥʔτ ৽نϢʔβొ σβΠϯมߋ
Ͳ͏ςετΛ ॻ͍͍͔ͯ͘
w ςετ͕ͳ͍ͷطʹઃܭ͕ѱ͍ஹީ w ઃܭ࣮Λม͑Δͷ͕લఏ w ࣮ͷςετΛॻ͔ͳ͍͜ͱ w ςετ͕Χόʔ͢Δൣғʹ༡ͼΛ࣋ͨ ͤɺΧόʔൣғΛϦϑΝΫλϦϯά w
ঢ়گʹԠͯ͡&&ςετΛ͍͜ͳ͢ ઃܭͷՄಈҬΛ֬อ͢Δ
w ࠷ॳ͔Βશ෦Ζ͏ͱ͠ͳ͍ w ςετۦಈʹͩ͜ΘΔͳ w ςετϑΝʔετʹͩ͜ΘΔͳ w ʮϢχοτʯςετʹͩ͜ΘΔͳ w ςετͷ࣮ߦʹͩ͜ΘΔͳ
w ςετͷཏੑʹͩ͜ΘΔͳ ͩ͜ΘΔͳ
w ྑ͍Ϣχοτςετͷࢦඪʹ༏ઌ ͕͋Δ w ࠶ݱɺ܁Γฦ͠Մೳ 3FQFBUBCMF w ಠཱ͍ͯ͠Δ *OEFQFOEFOU
w ଞͦΕ͔ΒͰ͍͍ ͩ͜ΘΖ͏
w ߹෦ͷݕ౼ͱۛຯ w ߜΓࠐΈͷൃݟͱґଘͷ w ࠶ݱੑ͋Δςετϋʔωεͷඋ w ूதฤू )ZQFSBXBSF&EJUJOH
w ίϯύΠϥ*%&·͔ͤ w ༷Խςετ w ࢼߦϦϑΝΫλϦϯά ϨΨγʔίʔυվળͷٕ๏ ৄ͘͠ σϞͰ
σϞطʹୀ৬ͨ͠ ઌഐ͕ॻ͍ͨ ṖͷίʔυΛҾ͖ܧ͙
IUUQTXXXqJDLSDPNQIPUPTUPNQBHFOFU ςετ࣭Λ্͛ͳ͍
w ࣭͕ʮΘ͔ΔʯΑ͏ʹͳΔ w Θ͔Δ͜ͱͦ͜େࣄ w ςετΛॻ͚ͩ͘Ͱɺྑ͘ͳΒͳ͍ w ମॏܭʹΔ͚ͩͰ૫ͤͳ͍ w ࣭Λ্͛Δͷઃܭͱϓϩάϥϛϯά
w ࠶ઃܭͱϦϑΝΫλϦϯάΛςετͰࢧ͑Δ ςετ࣭Λ্͛ͳ͍
lςετͰ্࣭͕Βͳ͍ Ͱ͢Αɻςετ͋͘·Ͱ ࣭Λ͋͛Δ͖͔͚ͬɻ࣭Λ͋ ͛ΔͷϓϩάϥϛϯάͰ͢ɻ ͜Εେੲ͔Βͦ͏ɻz
w ߹෦ͷݕ౼ͱۛຯ w ߜΓࠐΈͷൃݟͱґଘͷ w ࠶ݱੑ͋Δςετϋʔωεͷඋ w ूதฤू )ZQFSBXBSF&EJUJOH
w ίϯύΠϥ*%&·͔ͤ w ༷Խςετ w ࢼߦϦϑΝΫλϦϯά ͝ਗ਼ௌ͋Γ͕ͱ͏͍͟͝·ͨ͠