js delete duplicates from array
const names = ['John', 'Paul', 'George', 'Ringo', 'John'];
let unique = [...new Set(names)];
console.log(unique); // 'John', 'Paul', 'George', 'Ringo'js delete duplicates from array
const names = ['John', 'Paul', 'George', 'Ringo', 'John'];
let unique = [...new Set(names)];
console.log(unique); // 'John', 'Paul', 'George', 'Ringo'how to remove duplicates in array in javascript
const numbers = [1 , 21, 21, 34 ,12 ,34 ,12];
const removeRepeatNumbers = array => [... new Set(array)]
removeRepeatNumbers(numbers) // [ 1, 21, 34, 12 ]prevent duplicate entries in javascript array
if (array.indexOf(value) === -1) array.push(value);remove duplicates array javascript
function uniqByKeepFirst(a, key) {
let seen = new Set();
return a.filter(item => {
let k = key(item);
return seen.has(k) ? false : seen.add(k);
});
}
function uniqByKeepLast(a, key) {
return [
...new Map(
a.map(x => [key(x), x])
).values()
]
}
//
data = [
{a:1, u:1},
{a:2, u:2},
{a:3, u:3},
{a:4, u:1},
{a:5, u:2},
{a:6, u:3},
];
console.log(uniqByKeepFirst(data, it => it.u))
console.log(uniqByKeepLast(data, it => it.u))remove duplicate item from array javascript
function remove_duplicates(arr) {
var obj = {};
var ret_arr = [];
for (var i = 0; i < arr.length; i++) {
obj[arr[i]] = true;
}
for (var key in obj) {
ret_arr.push(key);
}
return ret_arr;
}Copyright © 2021 Codeinu
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