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const union = (...arr) => [...new Set(arr.flat())];// Exampleunion([1, 2], [2, 3], [3]); // [1, 2, 3]
var arr = [{"success": true,"data": [{"id": "ipi_1KrrbvDOiB2klwsKhuqUWqt1","object": "issuing.transaction","amount": -2743,"amount_details": {"atm_fee": null},"authorization": "iauth_1KrrbuDOiB2klwsKoFjQZhhd","balance_transaction": "txn_1KrrbwDOiB2klwsK1YkjJJRi","card": "ic_1Krqe5DOiB2klwsK44a35eiE","cardholder": "ich_1KrqL8DOiB2klwsKtBnZhzYr","created": 1650753567,"currency": "usd","dispute": null,"livemode": false,"merchant_amount": -2743,"merchant_currency": "usd","merchant_data": {"category": "advertising_services","category_code": "7311","city": "San Francisco","country": "US","name": "Aeros Marketing, LLC","network_id": "1234567890","postal_code": "94103","state": "CA"},"metadata": {},"type": "capture","wallet": null},{"id": "ipi_1Krrbvc62B2klwsKhuqUWqt1","object": "issuing.transaction","amount": -9999,"amount_details": {"atm_fee": null},"authorization": "iauth_1KrrbuDOiB2klwsKoFjQZhhd","balance_transaction": "txn_1KrrbwDOiB2klwsK1YkjJJRi","card": "ic_1Krqe5DOiB2klwsK44a35eiE","cardholder": "ich_1KrqL8DOiB2klwsKtBnZhzYr","created": 1650753567,"currency": "USD","dispute": null,"livemode": false,"merchant_amount": -9999,"merchant_currency": "usd","merchant_data": {"category": "fast_food","category_code": "7311","city": "San Francisco","country": "US","name": "Aeros Marketing, LLC","network_id": "1234567890","postal_code": "94103","state": "CA"},"metadata": {},"type": "capture","wallet": null}]}];const reduced = arr.reduce((prev, curr) => {prev.push({amount: curr.data[0].merchant_amount,id: curr.data[0].id,currency: curr.data[0].currency,category: curr.data[0].merchant_data.category});console.log(prev)return prev;}, []);
const celsiusToFahrenheit = (celsius) => celsius * 9/5 + 32;const fahrenheitToCelsius = (fahrenheit) => (fahrenheit - 32) * 5/9;// ExamplescelsiusToFahrenheit(15); // 59celsiusToFahrenheit(0); // 32celsiusToFahrenheit(-20); // -4fahrenheitToCelsius(59); // 15fahrenheitToCelsius(32); // 0
const nums = [1, 2, 3];const strs = Array.from('est');nums.push(6);nums.push(4, 9);strs.unshift('t');nums.length; // 6nums[nums.length - 1]; // 9strs[0]; // 't'strs[2]; // 's'nums.slice(1, 3); // [2, 3]nums.map(n => n * 2); // [2, 4, 6, 12, 8, 18]nums.filter(n => n % 2 === 0); // [2, 6, 4]nums.reduce((a, n) => a + n, 0); // 25strs.reverse(); // ['t', 's', 'e', 't']strs.join(''); // 'test'const nums = new Set([1, 2, 3]);nums.add(4);nums.add(1);nums.add(5);nums.add(4);nums.size; // 5nums.has(4); // truenums.delete(4);nums.has(4); // false[...nums]; // [1, 2, 3, 5]nums.clear();nums.size; // 0const items = new Map([[1, { name: 'John' }],[2, { name: 'Mary' }]]);items.set(4, { name: 'Alan' });items.set(2, { name: 'Jeff' });items.size; // 3items.has(4); // trueitems.get(2); // { name: 'Jeff' }items.delete(2);items.size; // 2[...items.keys()]; // [1, 4][...items.values()]; // [{ name: 'John' }, { name: 'Alan' }]items.clear();items.size; // 0
// promisify(f, true) to get array of resultsfunction promisify(f, manyArgs = false) {return function (...args) {return new Promise((resolve, reject) => {function callback(err, ...results) { // our custom callback for fif (err) {reject(err);} else {// resolve with all callback results if manyArgs is specifiedresolve(manyArgs ? results : results[0]);}}args.push(callback);f.call(this, ...args);});};}// usage:f = promisify(f, true);f(...).then(arrayOfResults => ..., err => ...);
const quickSort = arr => {const a = [...arr];if (a.length < 2) return a;const pivotIndex = Math.floor(arr.length / 2);const pivot = a[pivotIndex];const [lo, hi] = a.reduce((acc, val, i) => {if (val < pivot || (val === pivot && i != pivotIndex)) {acc[0].push(val);} else if (val > pivot) {acc[1].push(val);}return acc;},[[], []]);return [...quickSort(lo), pivot, ...quickSort(hi)];};console.log(quickSort([1, 6, 1, 5, 3, 2, 1, 4])) // [1, 1, 1, 2, 3, 4, 5, 6]