Quick JS collections snippets

snippets.js

/* 
 * Snippets collected during development: made by myself or found on StackOverflow/GitHub. 
 * Collection will grow in time.
 * Enjoy.
*/

// --- removing duplicates from an array ---
[2, 4, 5, 2, 6, 4].filter((el, i, arr) => arr.indexOf(el) === i);
[2, 4, 5, 2, 6, 4].reduce((acc, curr) => acc.includes(curr) ? acc : [...acc, curr], []);
[2, 4, 5, 2, 6, 4].reduce((acc, curr) => acc.includes(curr) ? acc : acc.concat(curr), []);
[...new Set([2, 4, 5, 2, 6, 4])];

// --- flattening array of arrays ---
[[2,4], [5,2,6], [4]].reduce((acc, curr) => acc.concat(curr));

// --- last element of array ---
const arr = [2, 4, 5, 2, 6, 4];
arr[arr.length - 1];
const [last] = arr.splice(-1);