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// Vanilla JS Solution:var app = document.getElementById('app');var typewriter = new Typewriter(app, { loop: true });typewriter.typeString("I'm John and I'm a super cool web developer").pauseFor(3000).deleteChars(13) // "web developer" = 13 characters.typeString("person to talk with!") // Will display "I'm John and I'm a super cool person to talk with!".start();// React Solution:import Typewriter from 'typewriter-effect';<Typewriteroptions={{ loop: true }}onInit={typewriter => {typewriter.typeString("I'm John and I'm a super cool web developer").pauseFor(3000).deleteChars(13) // "web developer" = 13 characters.typeString("person to talk with!") // Will display "I'm John and I'm a super cool person to talk with!".start();}}/>
const countSubstrings = (str, searchValue) => {let count = 0,i = 0;while (true) {const r = str.indexOf(searchValue, i);if (r !== -1) [count, i] = [count + 1, r + 1];else return count;}};countSubstrings('tiktok tok tok tik tok tik', 'tik'); // 3countSubstrings('tutut tut tut', 'tut'); // 4
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 binarySearch = (arr, item) => {let l = 0,r = arr.length - 1;while (l <= r) {const mid = Math.floor((l + r) / 2);const guess = arr[mid];if (guess === item) return mid;if (guess > item) r = mid - 1;else l = mid + 1;}return -1;};binarySearch([1, 2, 3, 4, 5], 1); // 0binarySearch([1, 2, 3, 4, 5], 5); // 4binarySearch([1, 2, 3, 4, 5], 6); // -1
/*** @param {number[]} nums* @return {number[]}*/var productExceptSelf = function(nums) {var output = [];var leftMult = 1;var rightMult = 1;for (var i=nums.length - 1; i >= 0; i--) {output[i] = rightMult;rightMult *= nums[i];console.log({output: JSON.stringify(output), i})}for (var j=0; j < nums.length; j++) {output[j] *= leftMult;leftMult *= nums[j];console.log({output: JSON.stringify(output), j})}return output;};console.log(productExceptSelf([1, 2, 3, 4]))
class TreeNode {constructor(key, value = key, parent = null) {this.key = key;this.value = value;this.parent = parent;this.children = [];}get isLeaf() {return this.children.length === 0;}get hasChildren() {return !this.isLeaf;}}class Tree {constructor(key, value = key) {this.root = new TreeNode(key, value);}*preOrderTraversal(node = this.root) {yield node;if (node.children.length) {for (let child of node.children) {yield* this.preOrderTraversal(child);}}}*postOrderTraversal(node = this.root) {if (node.children.length) {for (let child of node.children) {yield* this.postOrderTraversal(child);}}yield node;}insert(parentNodeKey, key, value = key) {for (let node of this.preOrderTraversal()) {if (node.key === parentNodeKey) {node.children.push(new TreeNode(key, value, node));return true;}}return false;}remove(key) {for (let node of this.preOrderTraversal()) {const filtered = node.children.filter(c => c.key !== key);if (filtered.length !== node.children.length) {node.children = filtered;return true;}}return false;}find(key) {for (let node of this.preOrderTraversal()) {if (node.key === key) return node;}return undefined;}}const tree = new Tree(1, 'AB');tree.insert(1, 11, 'AC');tree.insert(1, 12, 'BC');tree.insert(12, 121, 'BG');[...tree.preOrderTraversal()].map(x => x.value);// ['AB', 'AC', 'BC', 'BCG']tree.root.value; // 'AB'tree.root.hasChildren; // truetree.find(12).isLeaf; // falsetree.find(121).isLeaf; // truetree.find(121).parent.value; // 'BC'tree.remove(12);[...tree.postOrderTraversal()].map(x => x.value);// ['AC', 'AB']