{"id":44,"date":"2026-05-23T15:04:29","date_gmt":"2026-05-23T15:04:29","guid":{"rendered":"https:\/\/jobswalkin.com\/blogs\/?p=44"},"modified":"2026-05-23T19:00:34","modified_gmt":"2026-05-23T19:00:34","slug":"v-v-i-group-objects-by-property-in-javascript","status":"publish","type":"post","link":"https:\/\/jobswalkin.com\/blogs\/javascript\/v-v-i-group-objects-by-property-in-javascript\/","title":{"rendered":"Group Objects by Property in JavaScript"},"content":{"rendered":"\n<ul class=\"wp-block-list\">\n<li>Adds current object into that city array.<\/li>\n\n\n\n<li>Real World Use Cases<\/li>\n\n\n\n<li>Group employees by department<\/li>\n\n\n\n<li>Group students by class<\/li>\n\n\n\n<li>Group products by category<\/li>\n\n\n\n<li>Group jobs by city<\/li>\n\n\n\n<li>Group candidates by skills<\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>const users = &#91;\n    { name: \"Raj\", city: \"Bangalore\" },\n    { name: \"Amit\", city: \"Delhi\" },\n    { name: \"John\", city: \"Bangalore\" }\n];\n\nconst grouped = users.reduce((acc, curr) => {\n\t\n\t\/\/console.log(curr);\n\t\n    if (!acc&#91;curr.city]) {\n        acc&#91;curr.city] = &#91;];\n    }\n\n    acc&#91;curr.city].push(curr);\n\n    return acc;\n}, {});\n\nconsole.log(grouped);\n\n\/*\n  output : \n\t  {\n\t\t  Bangalore: &#91;\n\t\t\t{ name: 'Raj', city: 'Bangalore' },\n\t\t\t{ name: 'John', city: 'Bangalore' }\n\t\t  ],\n\t\t  Delhi: &#91; { name: 'Amit', city: 'Delhi' } ]\n\t  }\n*\/\n\nUnderstanding Step by Step\nacc\n\nacc means accumulator.\n\nInitially:\n\n{}\n\nIt stores the final grouped result.\n\ncurr\n\ncurr means current object.\n\nFirst iteration:\n\n{ name: \"Raj\", city: \"Bangalore\" }\nPART 1\nif (!acc&#91;curr.city]) {\n    acc&#91;curr.city] = &#91;];\n}\nWhat is curr.city ?\n\nFor first object:\n\ncurr.city\n\nValue:\n\n\"Bangalore\"\n\nSo this becomes:\n\nacc&#91;\"Bangalore\"]\nFirst Iteration\n\nInitially:\n\nacc = {}\n\nCheck:\n\nif (!acc&#91;\"Bangalore\"])\n\nSince it does not exist:\n\nundefined\n\nCondition becomes TRUE.\n\nThen:\n\nacc&#91;\"Bangalore\"] = &#91;];\n\nNow accumulator becomes:\n\n{\n   Bangalore: &#91;]\n}\nPART 2\nacc&#91;curr.city].push(curr);\n\nThis becomes:\n\nacc&#91;\"Bangalore\"].push(curr)\n\nMeaning:\n\n&#91;].push({ name: \"Raj\", city: \"Bangalore\" })\n\nNow:\n\n{\n   Bangalore: &#91;\n      { name: \"Raj\", city: \"Bangalore\" }\n   ]\n}\nSecond Iteration\n\nCurrent object:\n\n{ name: \"Amit\", city: \"Delhi\" }\n\nCheck:\n\nif (!acc&#91;\"Delhi\"])\n\nDelhi does not exist.\n\nCreate:\n\nacc&#91;\"Delhi\"] = &#91;];\n\nThen push:\n\nacc&#91;\"Delhi\"].push(curr)\n\nNow:\n\n{\n   Bangalore: &#91;\n      { name: \"Raj\", city: \"Bangalore\" }\n   ],\n\n   Delhi: &#91;\n      { name: \"Amit\", city: \"Delhi\" }\n   ]\n}\nThird Iteration\n\nCurrent:\n\n{ name: \"John\", city: \"Bangalore\" }\n\nCheck:\n\nif (!acc&#91;\"Bangalore\"])\n\nNow Bangalore already exists:\n\n&#91;\n   { name: \"Raj\", city: \"Bangalore\" }\n]\n\nCondition becomes FALSE.\n\nSo it skips array creation.\n\nThen:\n\nacc&#91;\"Bangalore\"].push(curr)\n\nFinal Output:\n\n{\n   Bangalore: &#91;\n      { name: \"Raj\", city: \"Bangalore\" },\n      { name: \"John\", city: \"Bangalore\" }\n   ],\n\n   Delhi: &#91;\n      { name: \"Amit\", city: \"Delhi\" }\n   ]\n}\nSimple Meaning\nThis line:\nacc&#91;curr.city] = &#91;];\n\nCreates a new array if city does not exist.\n\nThis line:\nacc&#91;curr.city].push(curr);\n\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":47,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[6],"class_list":["post-44","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-javascript","tag-reducer"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.6 - 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