underscore/lodash unique by multiple properties

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Use Lodash’s uniqWith method:

_.uniqWith(array, [comparator])

This method is like _.uniq except that it accepts comparator which is invoked to compare elements of array. The order of result values is determined by the order they occur in the array. The comparator is invoked with two arguments: (arrVal, othVal).

When the comparator returns true, the items are considered duplicates and only the first occurrence will be included in the new array.

Example:
I have a list of locations with latitude and longitude coordinates — some of which are identical — and I want to see the list of locations with unique coordinates:

const locations = [
  {
    name: "Office 1",
    latitude: -30,
    longitude: -30
  },
  {
    name: "Office 2",
    latitude: -30,
    longitude: 10
  },
  {
    name: "Office 3",
    latitude: -30,
    longitude: 10
  }
];

const uniqueLocations = _.uniqWith(
  locations,
  (locationA, locationB) =>
    locationA.latitude === locationB.latitude &&
    locationA.longitude === locationB.longitude
);

// Result has Office 1 and Office 2

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