find duplicate values in array object javascript
const values = [{id: 10, name: 'someName1'}, {id: 10, name: 'someName2'}, {id: 11, name:'someName3'}, {id: 12, name: 'someName4'}];
const lookup = values.reduce((a, e) => {
a[e.id] = ++a[e.id] || 0;
return a;
}, {});
console.log(values.filter(e => lookup[e.id]));
Run code snippetHide resultsfind duplicate values in array object javascript
function getUnique(arr, comp) {
// store the comparison values in array
const unique = arr.map(e => e[comp])
// store the indexes of the unique objects
.map((e, i, final) => final.indexOf(e) === i && i)
// eliminate the false indexes & return unique objects
.filter((e) => arr[e]).map(e => arr[e]);
return unique;
}
console.log(getUnique(arr,'id'));Copyright © 2021 Codeinu
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