remove duplicates from array of objects javascript
// BEST ANSWER - LINEAR TIME SOLUTION
const seen = new Set();
const arr = [
{ id: 1, name: "test1" },
{ id: 2, name: "test2" },
{ id: 2, name: "test3" },
{ id: 3, name: "test4" },
{ id: 4, name: "test5" },
{ id: 5, name: "test6" },
{ id: 5, name: "test7" },
{ id: 6, name: "test8" }
];
const filteredArr = arr.filter(el => {
const duplicate = seen.has(el.id);
seen.add(el.id);
return !duplicate;
});
let days = ["senin","senin","selasa","selasa","rabu","kamis", "rabu"];
let fullname = [{name: "john"}, {name: "jane"}, {name: "imelda"}, {name: "john"},{name: "jane"}];
// REMOVE DUPLICATE FOR ARRAY LITERAL
const arrOne = new Set(days);
console.log(arrOne);
const arrTwo = days.filter((item, index) => days.indexOf(item) == index);
console.log(arrTwo);
// REMOVE DUPLICATE FOR ARRAY OBJECT
const arrObjOne = [...new Map(person.map(item => [JSON.stringify(item), item])).values()];
console.log(arrObjOne);
const arrObjTwo = Array.from(new Set(person.map(JSON.stringify))).map(JSON.parse);
console.log(arrObjTwo);
var arrayWithDuplicates = [
{"type":"LICENSE", "licenseNum": "12345", state:"NV"},
{"type":"LICENSE", "licenseNum": "A7846", state:"CA"},
{"type":"LICENSE", "licenseNum": "12345", state:"OR"},
{"type":"LICENSE", "licenseNum": "10849", state:"CA"},
{"type":"LICENSE", "licenseNum": "B7037", state:"WA"},
{"type":"LICENSE", "licenseNum": "12345", state:"NM"}
];
function removeDuplicates(originalArray, prop) {
var newArray = [];
var lookupObject = {};
for(var i in originalArray) {
lookupObject[originalArray[i][prop]] = originalArray[i];
}
for(i in lookupObject) {
newArray.push(lookupObject[i]);
}
return newArray;
}
var uniqueArray = removeDuplicates(arrayWithDuplicates, "licenseNum");
console.log("uniqueArray is: " + JSON.stringify(uniqueArray));