Multi-value lodash filter on a key

Question

I am trying to find in how to find out an array of object filters with several key values. something similar to SQL - WHERE KEY in (val1, val2) lodash javascript library

Having said in the following example:

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

_.filter(...)

How to find users who are aged (34, 36) ?? numbers can also change runtime

Answer 1

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

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>

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You can also do this easily with vanilla JS (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);

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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

- :

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

The problem is that if you do this dynamically, you cannot have the same key in an object more than once.