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// `date` is a `Date` objectconst formatYmd = date => date.toISOString().slice(0, 10);// ExampleformatYmd(new Date()); // 2020-05-06
var invertTree = function(root) {const reverseNode = node => {if (node == null) {return null}reverseNode(node.left);reverseNode(node.right);let holdLeft = node.left;node.left = node.right;node.right = holdLeft;return node;}return reverseNode(root);};
class DoublyLinkedList {constructor() {this.nodes = [];}get size() {return this.nodes.length;}get head() {return this.size ? this.nodes[0] : null;}get tail() {return this.size ? this.nodes[this.size - 1] : null;}insertAt(index, value) {const previousNode = this.nodes[index - 1] || null;const nextNode = this.nodes[index] || null;const node = { value, next: nextNode, previous: previousNode };if (previousNode) previousNode.next = node;if (nextNode) nextNode.previous = node;this.nodes.splice(index, 0, node);}insertFirst(value) {this.insertAt(0, value);}insertLast(value) {this.insertAt(this.size, value);}getAt(index) {return this.nodes[index];}removeAt(index) {const previousNode = this.nodes[index - 1] || null;const nextNode = this.nodes[index + 1] || null;if (previousNode) previousNode.next = nextNode;if (nextNode) nextNode.previous = previousNode;return this.nodes.splice(index, 1);}clear() {this.nodes = [];}reverse() {this.nodes = this.nodes.reduce((acc, { value }) => {const nextNode = acc[0] || null;const node = { value, next: nextNode, previous: null };if (nextNode) nextNode.previous = node;return [node, ...acc];}, []);}*[Symbol.iterator]() {yield* this.nodes;}}const list = new DoublyLinkedList();list.insertFirst(1);list.insertFirst(2);list.insertFirst(3);list.insertLast(4);list.insertAt(3, 5);list.size; // 5list.head.value; // 3list.head.next.value; // 2list.tail.value; // 4list.tail.previous.value; // 5[...list.map(e => e.value)]; // [3, 2, 1, 5, 4]list.removeAt(1); // 2list.getAt(1).value; // 1list.head.next.value; // 1[...list.map(e => e.value)]; // [3, 1, 5, 4]list.reverse();[...list.map(e => e.value)]; // [4, 5, 1, 3]list.clear();list.size; // 0
const compactObject = val => {const data = Array.isArray(val) ? val.filter(Boolean) : val;return Object.keys(data).reduce((acc, key) => {const value = data[key];if (Boolean(value))acc[key] = typeof value === 'object' ? compactObject(value) : value;return acc;},Array.isArray(val) ? [] : {});};const obj = {a: null,b: false,c: true,d: 0,e: 1,f: '',g: 'a',h: [null, false, '', true, 1, 'a'],i: { j: 0, k: false, l: 'a' }};compactObject(obj);// { c: true, e: 1, g: 'a', h: [ true, 1, 'a' ], i: { l: 'a' } }
const getURLParameters = url =>(url.match(/([^?=&]+)(=([^&]*))/g) || []).reduce((a, v) => ((a[v.slice(0, v.indexOf('='))] = v.slice(v.indexOf('=') + 1)), a),{});
const getTimezone = () => Intl.DateTimeFormat().resolvedOptions().timeZone;// ExamplegetTimezone();