ͳͥ1SPYZʹ͍ͭͯ͢ͷ͔ w 3FHBSEJOHUIFCSPLFOQSPNJTFPG8FC $PNQPOFOUTͰ࠶ൃݟ w &4ͷղઆهࣄͰݟͨ͜ͱ͕͋ͬͨɺͬͨ͜ͱ ͳ͔ͬͨ http://robdodson.me/regarding-the-broken-promise- of-web-components/ w ௐͯΈΔͱɺ7VFʹ࠾༻͞ΕΔΑ͏ͳͷͰհ 3
1SPYZ֓ཁ w جຊతͳૢ࡞ ྫ͑ϓϩύςΟͷݕࡧɺೖɺྻڍɺؔͷىಈͳ Ͳ ʹ͍ͭͯಠࣗͷಈ࡞Λఆٛ wߏจ var p = new Proxy(target, handler); wҾ target λʔήοτͷΦϒδΣΫτ·ͨɺ1SPYZͰϥοϓ͢Δؔ handler ؔΛϓϩύςΟͱͯ࣋ͭ͠ΦϒδΣΫτ ͦͷؔͰɺ1SPYZʹରͯ͠ૢ࡞͕ߦΘΕͨ߹ͷڍಈΛఆٛ w ิ QͱUBSHFUಉ໊͡લͰΑ͍ 4
7VFͷ1SPYZؔ࿈ใ w 7VF1SPYZͳͲͷ৽͍͠"1*Λ͏ͨΊɺ*&ͳͲͷݹ͍ϒ ϥβΛαϙʔτ͠ͳ͍ IUUQTIBTIOPEFDPNBNBXJUIWVFKTUFBN DKJUMSLJBFXVWST w 3FBDUJWJUZJO7VFKTWT7VFKT w 7VFKTͰɺྻͷϓϩύςΟͷͷઃఆಈతͳϓϩύ ςΟͷՃΛ7VFTFUͰߦ͏ඞཁ͕͋Δ w 7VFKTͰɺྻͷϓϩύςΟͷͷઃఆಈతͳϓϩύ ςΟͷՃ1SPYZͰଞͷϓϩύςΟͱಉ༷ʹѻ͑Δ IUUQTCMPHDMPVECPPTUJPSFBDUJWJUZJOWVFKTWTWVFKT EDEEEDEG 7
ϝλϓϩάϥϛϯά w .FUBQSPHSBNNJOHJO&41BSU1SPYJFT https://www.keithcirkel.co.uk/metaprogramming- in-es6-part-3-proxies/ w ແݶʹνΣΠϯՄೳͳ"1*࡞ w NFUIPENJTTJOHϑοΫ࣮ w ྻڍܕ͔ΒHFU0XO1SPQFSUZ/BNFT
0CKFDULFZT
JOԋࢉࢠΛӅณ w 0CTFSWFSύλʔϯ 0CKFDUPCTFSWF ͷ࣮ 9