Run results for: array indexing forEach vs reduce 2

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.135 Safari/537.36 Edg/84.0.522.63

Browser: Chrome 84

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
reduce array key	652157.2 Ops/sec
foreach array key	516601.1 Ops/sec
foreach simple key	796843.0 Ops/sec

Script Preparation code:

var arr = [];
for (id=1;id<1000;id++) arr.push({id,name:Math.random().toString(36).substring(7)})
var pk = 'id,name';
var pkarr = pk.split(',')
var acc={};

Tests:

reduce array key
arr.reduce((acc,row) => { acc[pkarr.map((col)=>row[col]).join(',')]=row; return acc; },{})
foreach array key
arr.forEach(row => acc[pkarr.map((col)=>row[col]).join(',')]=row);
foreach simple key
arr.forEach(row => acc[row.id+','+row.name]=row);
foreach simple template
arr.forEach(row => acc[`${row.id},${row.name}`]=row);
reduce simple key
arr.reduce((acc,row) => { acc[row.id+','+row.name]=row; return acc; },{})
reduce simple template
arr.reduce((acc,row) => { acc[`${row.id},${row.name}`]=row; return acc; },{})

Run results for: array indexing forEach vs reduce 2

reduce array key

foreach array key

foreach simple key

foreach simple template

reduce simple key

reduce simple template