javascript array every find if there are duplicates code example
Example 1: javascript get duplicates in array
function getDuplicateArrayElements(arr){
var sorted_arr = arr.slice().sort();
var results = [];
for (var i = 0; i < sorted_arr.length - 1; i++) {
if (sorted_arr[i + 1] === sorted_arr[i]) {
results.push(sorted_arr[i]);
}
}
return results;
}
var colors = ["red","orange","blue","green","red","blue"];
var duplicateColors= getDuplicateArrayElements(colors);//["blue", "red"]
Example 2: how to get duplicate values from array in javascript
var input = [1, 2, 3, 1, 3, 1];
var duplicates = input.reduce(function(acc, el, i, arr) {
if (arr.indexOf(el) !== i && acc.indexOf(el) < 0) acc.push(el); return acc;
}, []);
document.write(duplicates); // = 1,3 (actual array == [1, 3])