Run results for: find duplicates

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.87 Safari/537.36

Browser: Chrome 78

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
map filter	1223917.0 Ops/sec
reduce	1552536.0 Ops/sec
lodash	520442.9 Ops/sec

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/2.4.2/lodash.min.js'></script>

Script Preparation code:

function getModels() {
  const n = 1000;
  return new Array(n).fill(0).map((_, i) => ({
    id: i,
    value: Math.floor(Math.random() * n)
  }));
};

Tests:

map filter
const models = getModels(); const values = models.map((model) => model.value); models.forEach((model) => { const modelValue = model.value; const hasDuplicates = values.filter((value) => value === modelValue).length > 1; hasDuplicates && (model.isDuplicate = true); });
reduce
const models = getModels(); const valueMap = models.reduce((result, model) => (result[model.value] ? ++result[model.value] : result[model.value] = 1) && result, {}) models.forEach((model) => { valueMap[model.value] > 1 && (model.isDuplicate = true); });
lodash
const byValue = _.groupBy(getModels(), (model) => model.value); Object.values(byValue).forEach((models) => { const hasDuplicates = models.length > 1; hasDuplicates && models.forEach((model) => (model.isDuplicate = true)); });

Run results for: find duplicates

solutions to finding duplicates in array

map filter

reduce

lodash