Run results for: obj vs array again

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36

Browser: Chrome 85

Operating system: Mac OS X 10.15.2

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
update in array	101810.4 Ops/sec
update in obj	1503.3 Ops/sec

Script Preparation code:

list = Array.from({
    length: 1000
}, (v, i) => ({
    id: 'id' + i
}));
obj = list.reduce((acc, cur) => {
    acc[cur.id] = cur;
    return acc;
}, {});

AخA
 
list = Array.from({    length: 1000}, (v, i) => ({    id: 'id' + i}));obj = list.reduce((acc, cur) => {    acc[cur.id] = cur;    return acc;}, {});

Tests:

update in array
const list2 = list.map(item => item.id === 'id500' ? {...item, updated: true} : item)
x

const list2 = list.map(item => item.id === 'id500' ? {...item, updated: true} : item)
update in obj
const obj2 = {...obj, id500: {...obj['id500'], updated: true}}
const obj2 = {...obj, id500: {...obj['id500'], updated: true}}

Run results for: obj vs array again

update in array

update in obj