Redux Setup
0 likes • Mar 11, 2021
JavaScript
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const shuffle = ([...arr]) => {let m = arr.length;while (m) {const i = Math.floor(Math.random() * m--);[arr[m], arr[i]] = [arr[i], arr[m]];}return arr;};const foo = [1, 2, 3];shuffle(foo); // [2, 3, 1], foo = [1, 2, 3]
const levenshteinDistance = (s, t) => {if (!s.length) return t.length;if (!t.length) return s.length;const arr = [];for (let i = 0; i <= t.length; i++) {arr[i] = [i];for (let j = 1; j <= s.length; j++) {arr[i][j] =i === 0? j: Math.min(arr[i - 1][j] + 1,arr[i][j - 1] + 1,arr[i - 1][j - 1] + (s[j - 1] === t[i - 1] ? 0 : 1));}}return arr[t.length][s.length];};levenshteinDistance('duck', 'dark'); // 2
const luhnCheck = num => {let arr = (num + '').split('').reverse().map(x => parseInt(x));let lastDigit = arr.splice(0, 1)[0];let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + ((val *= 2) > 9 ? val - 9 : val)),0);sum += lastDigit;return sum % 10 === 0;};luhnCheck('4485275742308327'); // trueluhnCheck(6011329933655299); // trueluhnCheck(123456789); // false
let nums = [1,2,3,1]var containsDuplicate = function(nums) {let obj = {};for(let i =0; i< nums.length; i++){if(obj[nums[i]]){obj[nums[i]] += 1;return true;}else{obj[nums[i]] = 1;}}return false;};console.log(containsDuplicate(nums));
const permutations = arr => {if (arr.length <= 2) return arr.length === 2 ? [arr, [arr[1], arr[0]]] : arr;return arr.reduce((acc, item, i) =>acc.concat(permutations([...arr.slice(0, i), ...arr.slice(i + 1)]).map(val => [item,...val,])),[]);};permutations([1, 33, 5]);// [ [1, 33, 5], [1, 5, 33], [33, 1, 5], [33, 5, 1], [5, 1, 33], [5, 33, 1] ]
const jwt = require("jsonwebtoken");const authToken = (req, res, next) => {const token = req.headers["x-auth-token"];try {req.user = jwt.verify(token, process.env.ACCESS_TOKEN_SECRET);next();} catch (err) {console.log(err.message);res.status(401).json({ msg: "Error authenticating token" });}};module.exports = authToken;