filter array of objects from string name to id

Question

I am trying to convert an array of objects containing string values to their id value based off other array of objects. Here are the arrays.

const employees = [
  {
    name: 'bob',
    department: 'sales',
    location: 'west'
  },
  {
    name:'fred',
    department: 'sales',
    location: 'west'
  },
  {
    name:'josh',
    department: 'inventory',
    location: 'east'
  },
  {
    name: 'mike',
    department: 'quality assurance',
    location: 'north'
  }
];

const departments = [
 {
    dep: 'sales',
    id: 12
 },
 {
    dep:'quality assurance',
    id: 11
 },
 {
    dep:'inventory',
    id: 13
 }
];

const locations = [
  {
    region: 'west',
    id: 3
  },
  {
    region:'north',
    id: 1
  },
  {
    region:'east',
    id: 2
  },
  {
    region:'south',
    id: 4
  }
];

I would like the converted employees array to look like this:

[
 {name:"bob", department: 12, location: 3},
 {name:"fred", department: 12, location: 3},
 {name:"josh", department: 13, location: 2},
 {name:"mike", department: 11, location: 1}
]

I've tried:

employees.forEach((row) => {
  row.department = departments.filter(depart => row.department === depart.dep)
  .reduce((accumulator, id) => id)
  row.department = row.department.id; // would like to remove this.
});
employees.forEach((row) => {
  row.location = locations.filter(loc => row.location === loc.region)
  .reduce((accumulator, id) => id);
  row.location = row.location.id; // would like to remove this part.
});

I get the desired results from using the forEach I have, but I think there is a better way of using .filter() and .reduce(). I would like help removing the last line of the two forEach statements where I have to set row.department = row.department.id and row.location = row.location.id

raina77ow · Accepted Answer · 2018-03-21 20:31:14Z

5

One possible approach:

const dehydratedEmployees = employees.map(emp => {
  const depId = departments.find(dep => dep.dep === emp.department).id;
  const locId = locations.find(loc => loc.location === loc.region).id;
  return { name: emp.name, department: depId, location: locId };
});

In other words, you can use Array.prototype.find() instead of filter-reduce combo. As .reduce() won't stop at the first successful search, .find() is both more efficient and concise. Just don't forget to apply polyfill for IE and other non-supportive browsers.

edited Mar 21, 2018 at 20:31

answered Mar 21, 2018 at 20:23

raina77ow

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Comments

Ori Drori · Accepted Answer · 2018-03-21 21:24:56Z

2

One solution is to create Map for departments and locations to eliminated nested loop when mapping employees.
Map can be created from a nested array: new Map([[key, value], [key, value]]):

const employees = [
  { name: 'bob', department: 'sales', location: 'west' },
  { name:'fred', department: 'sales', location: 'west' },
  { name:'josh', department: 'inventory', location: 'east' },
  { name: 'mike', department: 'quality assurance', location: 'north'}
];

const departments = [
 { dep: 'sales', id: 12 },
 { dep:'quality assurance', id: 11 },
 { dep:'inventory', id: 13}
];

const locations = [
  { region: 'west', id: 3 },
  { region:'north', id: 1},
  { region:'east', id: 2 },
  { region:'south', id: 4}
];

const departmentMap = new Map(departments.map(i => [i.dep, i.id]));
const locationMap = new Map(locations.map(i => [i.region, i.id]));
const result = employees.map(e => ({
  name: e.name,
  department: departmentMap.get(e.department),
  location: locationMap.get(e.location)
}))
console.log(result);

edited Mar 21, 2018 at 21:24

Ori Drori

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answered Mar 21, 2018 at 20:38

FisNaN

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1 Comment

Ori Drori Over a year ago

Welcome. Good answer :)

yajiv · Accepted Answer · 2018-03-21 20:55:14Z

Another possible approach. You can use Array.prototype.filter()(like below)

const employees=[{name:'bob',department:'sales',location:'west'},{name:'fred',department:'sales',location:'west'},{name:'josh',department:'inventory',location:'east'},{name:'mike',department:'quality assurance',location:'north'}];const departments=[{dep:'sales',id:12},{dep:'quality assurance',id:11},{dep:'inventory',id:13}];const locations=[{region:'west',id:3},{region:'north',id:1},{region:'east',id:2},{region:'south',id:4}]

var newArray=employees.map((x)=>{
    return { name: x.name,
    department: departments.filter(y=>y.dep === x.department)[0].id,
    location: locations.filter(y=>y.region===x.location)[0].id};
});
console.log(newArray);

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