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Nowadays we often deal a lot of JSON data, and array of data objects. What is the best way of filtering unique data of a data field/member property? With JavaScript latest ES6 and spread operator it can be done with just 1 line of javascript.

var data=[] ; //sample array fill up data with 10000 rows,

var uniqueCustomer=[…new Set(data.map(a=>a.customerID))];

Above will create a unique customerID from each of the record in data using customerID as property.

If the array contains no objects and property, data.map is no longer required.


  1. data.map, return customerID as array
  2. new Set, create a Set object that cannot be duplicate, those customerID that is duplicate will be discarded
  3. spread operator, apply new set created as a new array.