2b:null 2c:["$","title",null,{"children":"Performance of Maps vs Objects | Dominik Moritz | Observable"}] 31:[] 2f:{"id":"29a12f823292a5d9","slug":"performance-of-maps-vs-objects","title":"Performance of Maps vs Objects","thumbnail":"895414765480435f29c9d6f4d5e6fa6c4c7183f294c83250d6f7ee48ec43b26d","access_level":"public","create_time":"$D2021-01-22T08:56:53.188Z","update_time":"$D2021-01-22T09:42:04.179Z","view_time":null,"first_public_time":"$D2021-01-22T09:06:42.521Z","fork":false,"stars":1,"starred":false,"owner":{"type":"team","id":"448d844ff245547c","login":"domoritz","name":"Dominik Moritz","avatar_url":"https://avatars-next.observableusercontent.com/e528f496e8e47781dbdc92c47d89b1b19946a81d20c027823850f83467732c11","tier":"starter_2024"},"version":69,"publish_version":69,"role":null,"authored":false,"authors":[{"type":"individual","id":"2e169e421d94e0c5","login":"domoritz","name":"Dominik Moritz","avatar_url":"https://avatars-next.observableusercontent.com/e528f496e8e47781dbdc92c47d89b1b19946a81d20c027823850f83467732c11","tier":null}],"members":[{"type":"individual","id":"2e169e421d94e0c5","login":"domoritz","name":"Dominik Moritz","avatar_url":"https://avatars-next.observableusercontent.com/e528f496e8e47781dbdc92c47d89b1b19946a81d20c027823850f83467732c11","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"title":"Performance of Maps vs Objects","cells":[{"id":0,"value":"md`# Performance of Maps vs Objects\n\nJavaScript has a [Map](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map) data structure that is similar to Objects but has better support for iterations and generally behaves more like a standard map type. [MDN has a good comparison](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map#objects_vs._maps). But how fast are scans of Maps compared with Objects?`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":19,"value":"md`\n| Method (processing ${d3.format(',')(\n N\n)} rows) | Build | Scan (100 times) | Total |\n|--------|------:|-----:|------:|\n| Object (literal) | ${timeObjectLiteral[1]} ms | ${\n timeObjectLiteral[2]\n} ms | ${timeObjectLiteral[0]} ms |\n| Object (constructed) | ${timeBuildObject[1]} ms | ${\n timeBuildObject[2]\n} ms | ${timeBuildObject[0]} ms |\n| Map | ${timeMap[1]} ms | ${timeMap[2]} ms | ${timeMap[0]} ms |\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":50,"value":"md`_Do all methods generate the same result_? **${\n timeObjectLiteral[3] === timeBuildObject[3] &&\n timeObjectLiteral[3] === timeMap[3]\n ? 'Yes'\n : 'No'\n}!**`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":5,"value":"viewof N = html``","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":9,"value":"timeObjectLiteral = {\n const t0 = Date.now();\n const data = Array(N);\n\n for (let i = 0; i < N; ++i) {\n data[i] = {\n foo: 2,\n bar: 3,\n baz: 1\n };\n }\n\n const t1 = Date.now();\n\n let sum;\n for (let i = 0; i < 100; ++i) {\n sum = accessAll(data);\n }\n\n const t2 = Date.now();\n\n return [t2 - t0, t1 - t0, t2 - t1, sum];\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":29,"value":"timeBuildObject = {\n const t0 = Date.now();\n const data = Array(N);\n\n for (let i = 0; i < N; ++i) {\n const o = {};\n o.foo = 2;\n o.bar = 3;\n o.baz = 1;\n data[i] = o;\n }\n\n const t1 = Date.now();\n\n let sum;\n for (let i = 0; i < 100; ++i) {\n sum = accessAll(data);\n }\n\n const t2 = Date.now();\n\n return [t2 - t0, t1 - t0, t2 - t1, sum];\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":22,"value":"timeMap = {\n const t0 = Date.now();\n const data = Array(N);\n\n for (let i = 0; i < N; ++i) {\n const m = new Map();\n m.set('foo', 2);\n m.set('bar', 3);\n m.set('baz', 1);\n data[i] = m;\n }\n\n const t1 = Date.now();\n\n let sum;\n for (let i = 0; i < 100; ++i) {\n sum = accessAllMap(data);\n }\n\n const t2 = Date.now();\n\n return [t2 - t0, t1 - t0, t2 - t1, sum];\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":13,"value":"accessAll = function(data) {\n let sum = 0;\n for (let i = 0; i < N; ++i) {\n let o = data[i];\n sum += o.foo + o.bar + o.baz;\n }\n return sum;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":37,"value":"accessAllMap = function(data) {\n let sum = 0;\n for (let i = 0; i < N; ++i) {\n let o = data[i];\n sum += o.get('foo') + o.get('bar') + o.get('baz');\n }\n return sum;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":25,"value":"d3 = require('d3')","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"}],"files":"$W31","stdlib":"1","titling":"auto"}} 30:"$2f:body"