lodash filter on key with multiple values

Question

I am trying to find out in lodash javascript library , how to find out filter array of objects multiple values of key. something similar to SQL - WHERE KEY in (val1, val2)

Having said, with following example :

var users = [
   { 'user': 'barney', 'age': 36, 'active': true },
   { 'user': 'fred',   'age': 40, 'active': false },
   { 'user': 'Avding',   'age': 34, 'active': true }
];

_.filter(...)

How can I find users, who's age in (34, 36) ?? numbers can also change runtime

Answer 1

Lodash's filter accepts a predicate. You can create the predicate using partial application, so you can change the values easily:

 var users = [ { 'user': 'barney', 'age': 36, 'active': true }, { 'user': 'fred', 'age': 40, 'active': false }, { 'user': 'Avding', 'age': 34, 'active': true } ]; var predicate = function(start, end) { return function(user) { return _.inRange(user.age, start, end + 1); } } var result = _.filter(users, predicate(34, 36)); console.log('inRange', result); /** is equal predicate **/ var predicate = function() { var args = _.toArray(arguments); return function(user) { var equalToUserAge = _.partial(_.isEqual, user.age); return args.some(equalToUserAge); } } var result = _.filter(users, predicate(34, 40)); console.log('equals', result);

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.16.4/lodash.min.js"></script>

You can also do this easily with vanilla JS as well (the example uses ES6):

 var users = [ { 'user': 'barney', 'age': 36, 'active': true }, { 'user': 'fred', 'age': 40, 'active': false }, { 'user': 'Avding', 'age': 34, 'active': true } ]; const predicate1 = (start, end) => ({ age }) => age >= start && age <= end; const result1 = users.filter(predicate1(34, 36)); console.log('in range', result1); const predicate2 = (...args) => ({ age }) => args.some((num) => age === num); const result2 = users.filter(predicate2(34, 40)); console.log('is equal', result2);

Answer 2

const users = [
  { 'user': 'barney', 'age': 36, 'active': true },
  { 'user': 'fred',   'age': 40, 'active': false },
  { 'user': 'Avding',   'age': 34, 'active': true }
];

const minAge = 34;
const maxAge = 36;

const filtered = _.filter(users, (user) => {
  return user.age >= minAge && user.age <= maxAge;
});

Answer 3

This is old but I had the same issue. I don't know if it is efficient but the below function returns what I am looking for. I had to flatten the result to keep the same format as the input.

var users = [
    { 'user': 'barney', 'age': 36, 'active': true },
    { 'user': 'fred',   'age': 40, 'active': false },
    { 'user': 'Avding',   'age': 34, 'active': true }
];

var ages = [{"age": 36},{"age": 34}]

function filterAges(array, vals) {
    var result=[];
    for (i = 0; i < vals.length; i++) {
        result.push(_.filter( array, vals[i] ));
    }
    return _.flattenDepth(result, 1);
}

Answer 4

 var users = [ { user: 'barney', age: 36, active: true }, { user: 'fred', age: 40, active: false }, { user: 'travis', age: 34, active: true} ]; var result = [] var x = _.filter(users, function(o) { _.map([36,34], function(p) { if (o.age == p) { result.push(o); } }); }); console.log(result)

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js"></script>

Answer 5

You can do something like this:

_.filter( object, { 'age': '34', 'age': '24' } );

The issue is if you are making this dynamically you can not have the same key in an object more than once.