If you are working javascript then you need to understand these basic algorithm because these algorithm are very useful in your daily programming life.
Get uniq from array
// get uniq from array
const nums = [1, 2, 1, 1, 2, 1, 3, 4, 1 ];
const uniq = [...new Set(numbers)]; // => [ 1, 2, 3, 4 ]
const uniq2 = Array.from(new Set(numbers)); // => [ 1, 2, 3, 4 ]
Update an array object by property
// update an object in array by property
const initial = [ {id: 1, score: 1}, {id: 2, score: 2}, {id: 3, score: 4}];
const newVal = {id: 3, score: 3};
const updated = initial.map(x => x.id === newVal.id ? newVal : x);
console.log(updated); // => [ { id: 1, score: 1 }, { id: 2, score: 2 }, { id: 3, score: 3 } ]
Remove an object from array by property
// remove object from array by property
const removeId = 3;
const without3 = initial.filter(x => x.id !== removeId);
console.log(without3); // => [ { id: 1, score: 1 }, { id: 2, score: 2 } ]
Remove a key from an object
var a = {
foo: 'bar',
useful: 1,
useless: 2
}
const {useless, ...clean} = a;
console.log(clean); // => {foo: 'bar', useful: 1}
Merge an array of objects together
// merge an array of objects
const data = [ {a: 1}, {b: 2}, {c: 3} ];
const merged = data.reduce((res, obj) => ({...res, ...obj}), {});
console.log(merged); // => { a: 1, b: 2, c: 3 }
Flatten
// flatten an array of arrays
const arrayOfArray = [ [1, 2], [3, 4], [[5, 6]] ];
const flattened = arrayOfArray.reduce((res, a) => [...res, ...a], [] );
console.log(flattened); // => [1, 2, 3, 4, [5, 6]]
Subtract two Sets
// subtract two sets
const s1 = [ 1, 2, 3, 4, 5 ];
const s2 = [ 2, 4 ];
const subtracted = s1.filter(x => s2.indexOf(x) < 0);
console.log(subtracted);
