1//check one attribute
2let person = [{name: "john"}, {name: "jane"}, {name: "imelda"}, {name: "john"}];
3
4person = person.filter((item, index, self) =>
5  index === self.findIndex((t) => (
6    t.name === item.name
7  ))
8)
9
10//check two attributes
11let person = [{place: "uno", name: "john"}, {place: "duno", name: "jane"}, {place: "duno" ,name: "imelda"}, {place: "uno" ,name: "john"}];
12
13person = person.filter((item, index, self) =>
14  index === self.findIndex((t) => (
15    t.place === item.place && t.name === item.name
16  ))
17)

1var arrayWithDuplicates = [
2    {"type":"LICENSE", "licenseNum": "12345", state:"NV"},
3    {"type":"LICENSE", "licenseNum": "A7846", state:"CA"},
4    {"type":"LICENSE", "licenseNum": "12345", state:"OR"},
5    {"type":"LICENSE", "licenseNum": "10849", state:"CA"},
6    {"type":"LICENSE", "licenseNum": "B7037", state:"WA"},
7    {"type":"LICENSE", "licenseNum": "12345", state:"NM"}
8];
9
10function removeDuplicates(originalArray, prop) {
11     var newArray = [];
12     var lookupObject  = {};
13
14     for(var i in originalArray) {
15        lookupObject[originalArray[i][prop]] = originalArray[i];
16     }
17
18     for(i in lookupObject) {
19         newArray.push(lookupObject[i]);
20     }
21      return newArray;
22 }
23
24var uniqueArray = removeDuplicates(arrayWithDuplicates, "licenseNum");
25console.log("uniqueArray is: " + JSON.stringify(uniqueArray));

1arr.reduce((acc, current) => {
2  const x = acc.find(item => item.id === current.id);
3  if (!x) {
4    return acc.concat([current]);
5  } else {
6    return acc;
7  }
8}, []);

1// BEST ANSWER - LINEAR TIME SOLUTION
2
3const seen = new Set();
4const arr = [
5  { id: 1, name: "test1" },
6  { id: 2, name: "test2" },
7  { id: 2, name: "test3" },
8  { id: 3, name: "test4" },
9  { id: 4, name: "test5" },
10  { id: 5, name: "test6" },
11  { id: 5, name: "test7" },
12  { id: 6, name: "test8" }
13];
14
15const filteredArr = arr.filter(el => {
16  const duplicate = seen.has(el.id);
17  seen.add(el.id);
18  return !duplicate;
19});

1const arr = [
2  { id: 1, name: "test1" },
3  { id: 2, name: "test2" },
4  { id: 2, name: "test3" },
5  { id: 3, name: "test4" },
6  { id: 4, name: "test5" },
7  { id: 5, name: "test6" },
8  { id: 5, name: "test7" },
9  { id: 6, name: "test8" }
10];
11
12const filteredArr = arr.reduce((acc, current) => {
13  const x = acc.find(item => item.id === current.id);
14  if (!x) {
15    return acc.concat([current]);
16  } else {
17    return acc;
18  }
19}, []);
20

1arr.filter((v,i,a)=>a.findIndex(t=>(t.place === v.place && t.name===v.name))===i)