Lodash: Extract property, split array, get unique values

Question

In my JS project, I am using Lodash library to Extract property, split array, get unique values.

  var taskobj = [
      {'taskno':'a', 'team':'1,2'},
      {'taskno':'b', 'team':'3,4'},
      {'taskno':'c', 'team':'2,4'},
    ];

 //Looping through the object to convert string to array
  _.forEach(taskobj, function(value, key) {
    taskobj[key].team = _.split(taskobj[key].team,',');
  });

// using _.map to extract team and return array
// using _.flatten to flatten array
// using _.uniq to get unique values from flattned array.

return _.uniq(_.flatten(_.map(taskobj,'team')));
// logs - [1,2,3,4]

Is this the most efficient way to achieve this?

var teams = []; taskobj.forEach(o => teams.push(...o.team.split(','))); _.uniq(teams); You can modify this to add a condition to check if element exists in the teams array before pushing and remove uniq. — Tushar
– Tushar, Commented Jun 27, 2018 at 4:58

Taki · Accepted Answer · 2018-06-27 05:44:09Z

3

you can use reduce and start with a new Set() and add the values of team every time ( then convert it back to an array with the spread operator )

var taskobj = [
  {'taskno':'a', 'team':'1,2'},
  {'taskno':'b', 'team':'3,4'},
  {'taskno':'c', 'team':'2,4'},
];

var result = [...taskobj.reduce((acc, {team}) => {
  team.split(',').forEach(e => acc.add(e))
  return acc
}, new Set())]

console.log(result)

edited Jun 27, 2018 at 5:44

answered Jun 27, 2018 at 5:18

Taki

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Comments

ryeballar · Accepted Answer · 2018-06-27 05:35:26Z

1

This can be achieved by using lodash#flatMap with an iteratee that splits the team string into an array, which is then flattened by the mentioned function and then use lodash#uniq to get the final result.

var result = _.uniq(_.flatMap(taskobj, ({ team }) => team.split(',')));

var taskobj = [
    {'taskno':'a', 'team':'1,2'},
    {'taskno':'b', 'team':'3,4'},
    {'taskno':'c', 'team':'2,4'},
];

var result = _.uniq(_.flatMap(taskobj, ({ team }) => team.split(',')));

console.log(result);

.as-console-wrapper{min-height:100%;top:0}

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>

answered Jun 27, 2018 at 5:35

ryeballar

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4 Comments

Adarsh Madrecha Over a year ago

What is the meaning of ({ team }) => team.split(',')) I am relatively new to JS

Adarsh Madrecha Over a year ago

Got it, it's arrow function (shorthand for function without a name) Ref - stackoverflow.com/a/24900924/4050261

ryeballar Over a year ago

@AdarshMadrecha also note that the team string was extracted with the use of Object Destructuring

Adarsh Madrecha Over a year ago

I used lodash _.split(arr,',') instead of arr.split(',') as lodash takes care of null values.

Piyush Patel · Accepted Answer · 2018-06-27 05:10:19Z

1

Use simpler version

try this

var teams = [];
var taskobj = [
      {'taskno':'a', 'team':'1,2'},
      {'taskno':'b', 'team':'3,4'},
      {'taskno':'c', 'team':'2,4'},
    ];

taskobj.map(obj => {
  var teamSplit = obj.team.split(',');
  teams = [...teams, ...teamSplit];
})

var uniqTeams = _.uniq(teams);
console.log('teams', teams);
console.log('uniqTeams', uniqTeams)

JsBin link http://jsbin.com/bedawatira/edit?js,console

answered Jun 27, 2018 at 5:10

Piyush Patel

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