Run results for: reassigning an object with 10000 objects

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser: Chrome 120

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
index	48798.5 Ops/sec
map	33361.7 Ops/sec

Script Preparation code:

var array = [];

for (var i = 1; i <= 10000; i++) {
    array.push({ id: i, name: `Item ${i}` });
}


var newObject = { id: 8868, name: 'Updated Item 2' };

Tests:

index
var index = array.findIndex(item => item.id === newObject.id); var updatedArray; if (index !== -1) { updatedArray = [ ...array.slice(0, index), // Elements before the updated item newObject, // The updated item ...array.slice(index + 1) // Elements after the updated item ]; } else { // If the item isn't found, the array remains unchanged updatedArray = array; }
map
var arr = array.map(item => { if (item.id === newObject.id) { return newObject; } return item; });

Run results for: reassigning an object with 10000 objects

index

map