Get two array from array of objects

Question

I have an array of objects:

const dataset = [
  {name: 'Marie', year: 12, country: 'Canada'},
  {name: 'Jeff', year: 18, country: 'France'},
  {name: 'Joss', year: 10, country: 'Spain'},
  {name: 'Carrie', year: 45, country: 'Belgium'},
  {name: 'Linda', year: 32, country: 'France'},
]

I want two array: one with names and one with countries:

const names = ['Marie', 'Jeff', 'Joss', 'Carrie', 'Linda']
const countries = ['Canada', 'France', 'Spain', 'Belgium', 'France']

So, I usually do:

const names = dataset.map(e => e.name)
const countries = dataset.map(e => e.country)

Is there a simplest way possibly using a single loop?

Answer 1

I'm not sure this is any simpler but it does use only a single loop:

 const dataset={ ... }
 const names=[], countries=[]
 for (var d of dataset) { 
     names.push(d.name); 
     countries.push(d.country);
 }

Surprisingly, according to jsben.ch, this approach is about 6 times faster than running map twice.