Run results for: Map population

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36

Browser: Chrome 115

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
forEach	301659.4 Ops/sec
Map	311670.8 Ops/sec

Tests:

forEach
const oldState = { entities: [ {SomeProp: 'nonsense 1', SomeOtherProp: 'more nonsense 1', id: 1}, {SomeProp: 'nonsense 2', SomeOtherProp: 'more nonsense 2', id: 2}, {SomeProp: 'nonsense 3', SomeOtherProp: 'more nonsense 3', id: 3}, {SomeProp: 'nonsense 4', SomeOtherProp: 'more nonsense 4', id: 4}, {SomeProp: 'nonsense 5', SomeOtherProp: 'more nonsense 5', id: 5}, {SomeProp: 'nonsense 6', SomeOtherProp: 'more nonsense 6', id: 6}, ] }; var oldEntitiesById = new Map(); Object.values(oldState.entities).forEach(e => oldEntitiesById.set(e.id, e)); console.log(oldEntitiesById);
Map
const oldState = { entities: [ {SomeProp: 'nonsense 1', SomeOtherProp: 'more nonsense 1', id: 1}, {SomeProp: 'nonsense 2', SomeOtherProp: 'more nonsense 2', id: 2}, {SomeProp: 'nonsense 3', SomeOtherProp: 'more nonsense 3', id: 3}, {SomeProp: 'nonsense 4', SomeOtherProp: 'more nonsense 4', id: 4}, {SomeProp: 'nonsense 5', SomeOtherProp: 'more nonsense 5', id: 5}, {SomeProp: 'nonsense 6', SomeOtherProp: 'more nonsense 6', id: 6}, ] }; const oldEntitiesById = new Map(oldState.entities.map(element => [element.id, element])); console.log(oldEntitiesById);