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'removing duplicates in array javascript
let arr = [1,2,3,1,1,1,4,5]
let filtered = arr.filter((item,index) => arr.indexOf(item) === index)
console.log(filtered) // [1,2,3,4,5]javascript remove duplicate in arrays
// 1. filter()
function removeDuplicates(array) {
return array.filter((a, b) => array.indexOf(a) === b)
};
// 2. forEach()
function removeDuplicates(array) {
let x = {};
array.forEach(function(i) {
if(!x[i]) {
x[i] = true
}
})
return Object.keys(x)
};
// 3. Set
function removeDuplicates(array) {
array.splice(0, array.length, ...(new Set(array)))
};
// 4. map()
function removeDuplicates(array) {
let a = []
array.map(x =>
if(!a.includes(x) {
a.push(x)
})
return a
};
/THIS SITE/ "https://dev.to/mshin1995/back-to-basics-removing-duplicates-from-an-array-55he#comments"javascript dedupe array
const names = ['John', 'Paul', 'George', 'Ringo', 'John'];
let x = (names) => names.filter((v,i) => names.indexOf(v) === i)
x(names); // 'John', 'Paul', 'George', 'Ringo'js delete duplicates from array
const names = ['John', 'Paul', 'George', 'Ringo', 'John'];
let x = (names) => names.filter((v,i) => names.indexOf(v) === i)
x(names); // 'John', 'Paul', 'George', 'Ringo'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))Copyright © 2021 Codeinu
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