There is an interview question: what is the result of [] == ![] ? At first thought, I think the result will be false , below is my rationale: ![] is equal to !Boolean([]) : false [] will convert to a true value and a true value is not equal…

Problem Statement Coin Change - LeetCode You are given an integer array coins representing coins of different denominations and an integer amount representing a…leetcode.com Approach 1: Top-Down Dynamic Programming /** * @param {number[]} coins * @param {number} amount * @return {number} */ var coinChange = function(coins, amount) { return coinChangeMomorized(coins, amount, new Array(amount + 1)); };

The longest common subsequence problem is a classic computer science problem, the basis of data comparison programs such as the diff utility, and has applications in computational linguistics and bioinformatics. …

Problem statement Delete and Earn - LeetCode You are given an integer array nums. You want to maximize the number of points you get by performing the following…leetcode.com Approach 1: Top-down Dynamic Programming /** * @param {number[]} nums * @return {number} */ var deleteAndEarn = function(nums) { // 1. loop the nums, find max number const maxNum = Math.max(...nums); // 2. build map named as points, key is num, value is total point we can earn from this num const…

Sort lines alphabetically If you come across this code and want to sort lines alphabetically: * ASAP – As Soon As Possible * FYI - For Your Information * DIY – Do It Yourself * aka – Also Known As * RSVP – Please reply First, select those lines visually: Shift + V …

Declamation: this blog is a reading note of How does React bailout work in reconciliation — React Source Code Walkthrough 13 Demo Open this demo link, there is the famous button that increments when clicked. The main structure is: <A> <B> <C> <button/> <D/> </C> </B> <E> <F/> </E> </A> The…

Reading the ECMAScript specification is hard. What if we could debug the ECMAScript specification via Step-by-step execution? ESMeta ESMeta is such a cool tool. It could translate a JavaScript program into ECMAScript specification and support step-by-step debugging. Currently, it is in an alpha stage and supports only basic features such as: …

Problem Let us start with a problem and then explain it by reading the spec. Following is the problem: why ({}) instanceof Proxy throw an error instead of return false ? > ({}) instanceof Proxy Uncaught TypeError: Function has non-object prototype 'undefined' in instanceof check at [Symbol.hasInstance] …