{"id":17031,"date":"2026-07-27T12:56:33","date_gmt":"2026-07-27T03:56:33","guid":{"rendered":"http:\/\/www.gisdeveloper.co.kr\/?p=17031"},"modified":"2026-07-27T13:04:38","modified_gmt":"2026-07-27T04:04:38","slug":"javascript-%ec%99%80-%ea%b7%b8%eb%a6%ac%ea%b3%a0-%ec%97%b0%ec%82%b0%ec%9e%90%ec%97%90-%eb%8c%80%ed%95%98%ec%97%ac","status":"publish","type":"post","link":"http:\/\/www.gisdeveloper.co.kr\/?p=17031","title":{"rendered":"JavaScript, ??= \uc640 ||= \uadf8\ub9ac\uace0 ??= \uc5f0\uc0b0\uc790\uc5d0 \ub300\ud558\uc5ec"},"content":{"rendered":"

\ubab0\ub77c\ub3c4 \ub0b4 \ucf54\ub4dc \uc791\uc131\uc5d0 \uc804\ud600 \ubb38\uc81c\uac00 \ub418\uc9c0 \uc54a\ub294 \uc5f0\uc0b0\uc790\uc774\uc9c0\ub9cc \ub2e4\ub978 \uc0ac\ub78c\uc758 \ucf54\ub4dc\ub97c \ubd84\uc11d\ud558\ub2e4 \ubcf4\uba74 \ubcfc \uc218 \uc788\ub294 \uc5f0\uc0b0\uc790\uc774\ubbc0\ub85c \uc54c\uace0\ub294 \uc788\uc5b4\uc57c \ud558\uae30\uc5d0 \uc815\ub9ac\ud574 \ubd05\ub2c8\ub2e4.<\/p>\n

\uba3c\uc800 ??=<\/code> \uc5f0\uc0b0\uc790\ub294 Nullish Coalescing Assignment(\ub110 \ubcd1\ud569 \ub300\uc785 \uc5f0\uc0b0\uc790) \uc785\ub2c8\ub2e4. \uc88c\ubcc0\uc774 null<\/code> \uc774\uac70\ub098 undefined<\/code> \uc77c\ub54c\ub9cc \uc6b0\ubcc0\uc744 \ub300\uc785\ud569\ub2c8\ub2e4. \ucf54\ub4dc\ub85c \ubcf4\uba74 …<\/p>\n

\r\nx ??= y;\r\n<\/pre>\n
\uc704\uc758 \ucf54\ub4dc\ub294 \ub2e4\uc74c \ucf54\ub4dc\uc640 \ub3d9\uc77c\ud55c \ucf54\ub4dc\uc774\uba70 \uc544\ub798 \ucf54\ub4dc\ub85c \uc124\uba85\uc744 \ub300\uc2e0\ud569\ub2c8\ub2e4.<\/p>\n
\r\nif (x === null || x === undefined) {\r\n  x = y;\r\n}\r\n<\/pre>\n
\uc704\uc758 \ucf54\ub4dc\ub294 \ub2e4\uc74c \ucf54\ub4dc\uc640 \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\nx = x ?? y;\r\n<\/pre>\n
\ucc38\uace0\ub85c ??<\/code> \uc5f0\uc0b0\uc790\ub294 Nullish Coalescing Operator(\ub110 \ubcd1\ud569 \uc5f0\uc0b0\uc790)\uc790\ub85c ??=<\/code> \uc5f0\uc0b0\uc790\uc758 \ud615\uc81c\uc774\uae30\ub3c4 \ud569\ub2c8\ub2e4. \uc704\uc758 \ucf54\ub4dc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\nconst result = (a === null || a === undefined) ? b : a;\r\n<\/pre>\n
\uc790\ubc14\uc2a4\ud06c\ub9bd\ud2b8 \ud2b9\uc720\uc758 falsy \uac12\uc73c\ub85c \ud310\uc815\ub418\ub294 false<\/code>, \ube48\ubb38\uc790\uc5f4, 0<\/code>, NaN<\/code>, null<\/code>, undefined<\/code> \uac12 \uc911 \uc624\uc9c1 null<\/code>, undefined<\/code> \ub9cc\uc744 \ud2b9\ubcc4\ud558\uac8c \ucde8\uae09\ud574\uc8fc\ub294 \uac83\uc774 \ubc14\ub85c ?? \uc5f0\uc0b0\uc790\uc640 ??= \uc5f0\uc0b0\uc790\uc785\ub2c8\ub2e4.<\/p>\n
??=<\/code> \uc5f0\uc0b0\uc790\ub97c \uc0b4\ud3b4\ubcf4\ub2e4 \ubcf4\uba74 ||=<\/code> \uc5f0\uc0b0\uc790\uc640 &&=<\/code> \uc5f0\uc0b0\uc790\ub3c4 \ud568\uaed8 \uc0b4\ud3b4\ubd10\uc57c \ud63c\ub780\uc774 \uc5c6\uc2b5\ub2c8\ub2e4. \uba3c\uc800 ||=<\/code> \uc5f0\uc0b0\uc790\ub294 \uc88c\ubcc0\uc774 falsy \uac12\uc774\uba74 \ub300\uc785\ud569\ub2c8\ub2e4. \uc608\ub97c \ub4e4\uc5b4 \ub2e4\uc74c \ucf54\ub4dc\ub97c \ubcf4\uba74 …<\/p>\n
\r\nlet a = 0;\r\na ??= 100;\r\n\r\nconsole.log(a); \/\/ 0\r\n<\/pre>\n
&&=<\/code> \uc5f0\uc0b0\uc790\ub294 ||=<\/code> \uc5f0\uc0b0\uc790\uc640\ub294 \ubc18\ub300\ub85c \uc88c\ubcc0\uc774 truthy(falsy \uac12\uc774 \uc544\ub2cc \uac12)\uc774\uba74 \ub300\uc785\ud569\ub2c8\ub2e4. \uc608\ub4e4 \ub4e4\uc5b4 \ub2e4\uc74c \ucf54\ub4dc\ub97c \ubcf4\uba74 …<\/p>\n
\r\nlet z = \"abc\";\r\nz &&= \"xyz\";\r\nconsole.log(z); \/\/ \"xyz\"\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"
\ubab0\ub77c\ub3c4 \ub0b4 \ucf54\ub4dc \uc791\uc131\uc5d0 \uc804\ud600 \ubb38\uc81c\uac00 \ub418\uc9c0 \uc54a\ub294 \uc5f0\uc0b0\uc790\uc774\uc9c0\ub9cc \ub2e4\ub978 \uc0ac\ub78c\uc758 \ucf54\ub4dc\ub97c \ubd84\uc11d\ud558\ub2e4 \ubcf4\uba74 \ubcfc \uc218 \uc788\ub294 \uc5f0\uc0b0\uc790\uc774\ubbc0\ub85c \uc54c\uace0\ub294 \uc788\uc5b4\uc57c \ud558\uae30\uc5d0 \uc815\ub9ac\ud574 \ubd05\ub2c8\ub2e4. \uba3c\uc800 ??= \uc5f0\uc0b0\uc790\ub294 Nullish Coalescing Assignment(\ub110 \ubcd1\ud569 \ub300\uc785 \uc5f0\uc0b0\uc790) \uc785\ub2c8\ub2e4. \uc88c\ubcc0\uc774 null \uc774\uac70\ub098 undefined \uc77c\ub54c\ub9cc \uc6b0\ubcc0\uc744 \ub300\uc785\ud569\ub2c8\ub2e4. \ucf54\ub4dc\ub85c \ubcf4\uba74 … x ??= y; \uc704\uc758 \ucf54\ub4dc\ub294 \ub2e4\uc74c \ucf54\ub4dc\uc640 \ub3d9\uc77c\ud55c \ucf54\ub4dc\uc774\uba70 \uc544\ub798 \ucf54\ub4dc\ub85c \uc124\uba85\uc744 … <\/p>\n
\ub354 \ubcf4\uae30 “JavaScript, ??= \uc640 ||= \uadf8\ub9ac\uace0 ??= \uc5f0\uc0b0\uc790\uc5d0 \ub300\ud558\uc5ec”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[88,157],"tags":[],"class_list":["post-17031","post","type-post","status-publish","format-standard","hentry","category-javascript","category-typescript"],"_links":{"self":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/17031","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=17031"}],"version-history":[{"count":3,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/17031\/revisions"}],"predecessor-version":[{"id":17033,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/17031\/revisions\/17033"}],"wp:attachment":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=17031"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=17031"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=17031"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}