Run results for: String concatenation keys vs Multidimensional array keys - 3D

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.85 Safari/537.36

Browser: Chrome 90

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
String concatenation keys	6.0 Ops/sec
Multidimensional array keys	22.6 Ops/sec

Script Preparation code:

var numberList = Array(100).fill().map((x, i) => i);

var concatList = numberList.reduce((acc, i1) => {
  numberList.forEach((i2) => {
    numberList.forEach((i3) => {
      acc[`${i2}_${i2}_${i3}`] = 'string';
    });
  });
  return acc;
}, {});

var twoDList = numberList.reduce((acc, i1) => {
  numberList.forEach((i2) => {
    numberList.forEach((i3) => {
      if (!acc[i1]) acc[i1] = {};
      if (!acc[i1][i2]) acc[i1][i2] = {};
      acc[i1][i2][i3] = 'string';
    });
  });
  return acc;
}, {});

Tests:

String concatenation keys
numberList.forEach((i1) => { numberList.forEach((i2) => { numberList.forEach((i3) => { const variable = concatList[`${i2}_${i2}_${i3}`]; }); }); });
Multidimensional array keys
numberList.forEach((i1) => { numberList.forEach((i2) => { numberList.forEach((i3) => { const variable = twoDList[i2][i2][i3]; }); }); });