Run results for: so two map compare

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:101.0) Gecko/20100101 Firefox/101.0

Browser: Firefox 101

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
one map	527604.9 Ops/sec
two maps	357754.7 Ops/sec

Script Preparation code:

var primary =
[
 {recordId:123, type: "Primary" },
 {recordId:123, type: "Primary" },
 {recordId:123, type: "Primary" },
 {recordId:9393, type: "Primary" },
 {recordId:9393, type: "Primary" },
 {recordId:9393, type: "Primary" },
];

var secondary = [
 {recordId:123, type: "Secondary" },
 {recordId:123, type: "Secondary" },
 {recordId:9393, type: "Secondary" },
 {recordId:9393, type: "Secondary" },
 {recordId:9393, type: "Secondary" },
];

Tests:

one map
const missingRecords = [] const occurences = primary.reduce((acc, val) => acc.set(val.recordId, 1 + (acc.get(val.recordId) || 0)), new Map()); secondary.reduce((acc, val) => acc.set(val.recordId, (acc.get(val.recordId) || 0) - 1), occurences); for (const [skey, svalue] of occurences.entries()) { if (svalue !== 0) { missingRecords.push(skey); } }
two maps
const missingRecords = [] const primaryOccurences = primary.reduce((acc, val) => acc.set(val.recordId, 1 + (acc.get(val.recordId) || 0)), new Map()); const secondaryOccurences = secondary.reduce((acc, val) => acc.set(val.recordId, 1 + (acc.get(val.recordId) || 0)), new Map()); primaryOccurences.forEach((value, key) => { for (const [skey, svalue] of secondaryOccurences.entries()) { if (skey === key && value !== svalue) { missingRecords.push(key); } } })

Run results for: so two map compare

one map

two maps