Run results for: for vs. for-of vs. reduce (array to ID-keyed object) vs. while (reversed)

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.127 Safari/537.36

Browser: Chrome 100

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

Script Preparation code:

var itemCount = 10000
var items = new Array(itemCount)

for (var i = itemCount - 1; i >= 0; i--) {
  items[i] = { id: i, data: 920501 }
}

Tests:

for loop
const itemsById = {} for (let i = items.length - 1; i >= 0; i--) { itemsById[items[i].id] = items[i] }
for-of loop
const itemsById = {} for (const item of items) { itemsById[item.id] = item }
reduce
const itemsById = items.reduce((result, item) => { return { ...result, [item.id]: item } }, {})
while loop reverse
const itemsById = {} let i = items.length const arr = new Array(i) while(i--) itemsById[items[i].id] = items[i]