Explore Learn and Grow

1)[1,2]+[3,4] 2)var a=10; function b(){ console.log(a); var a=20 } b(); 3)Lambda size and how to use in s3 4)promise or next tick console setimeediate 5)profit problem 6)context vs event 7) NaN===NaN 8)layers in lambda 9)TTL in sqs, visibility timeout,default time 10)lambda size,defualt time 11)Can lambda trigger sns or viceversa 12)corre modules in nodejs

Introduction: MongoDB, a leading NoSQL database, offers unparalleled flexibility and scalability. However, achieving optimal query performance in MongoDB often relies on implementing effective indexing strategies. In this article, we'll delve into various indexing techniques and provide real-world examples to demonstrate their impact on query performance. Single Field Index: Single field indexes are ideal for accelerating queries that filter, sort, or search based on a specific field. Let's consider a scenario where we have a collection of user profiles, and we frequently query users by their username field: db.users.createIndex({ "username": 1 }) This index significantly speeds up queries like: db.users.find({ "username": "john_doe" }) Compound Index: Compound indexes are invaluable when queries involve multiple fields. Suppose we have a collection of products and often filter by both category and price: db.products.createIndex({ "category...

1) Advantages of TypeScript TypeScript offers several advantages over plain JavaScript: Static Typing: TypeScript introduces static typing, allowing developers to define types for variables, function parameters, and return values. This helps catch type-related errors during development and provides better code documentation. Enhanced Tooling: TypeScript provides improved tooling support, including features like code completion, refactoring, and navigation, which enhance developer productivity. Readability and Maintainability: With explicit type annotations, TypeScript code tends to be more readable and self-documenting. This makes it easier for developers to understand and maintain large codebases. Early Error Detection: TypeScript's type system catches many common errors at compile-time, such as type mismatches and missing properties, reducing the likelihood of runtime errors. Example: typescript Copy code // Plain JavaScript function greet(name) {     return 'Hello, ' + n...

  //Covered queries typeof typeof 1 cursor 3 larget number without sorting //How idexes are store internally string and number value //How to get 10 million data form mongodb without limit and skip //let s= "abcabcbb";//Output should be 3 abc // console.log('1')   // function demoFunction() { //  setTimeout(() => { //      console.log('2') //   }, 0) // }   // const promise = new Promise((resolve, reject) => { //  console.log('3') //  resolve('promise result') // })   // demoFunction()   // promise.then(() => { //  console.log('4') // })   // console.log('5'); //1 //3 //5 //4 //2 // Input: s = "abcabcbb" // Output: 3 function lengthOfLongestSubstring(s) { let maxLength = 0; let start = 0; const charIndexMap = new Map(); // Map to store the index of each character for (let end = 0; end < s.length; end++) { const char = s[end]; if (charIndexMap.has(char)) { ...

 1)Sonar qube bugs category 2)Type vs interface 3)groupBy with count: db. items . aggregate ([ { $group : { _id : "$category" , count : { $sum : 1 } }} ]) 4)factorial and fiboncaci series 5)

 1)Inheritence: Prototype inheritance is a core concept in JavaScript that allows objects to inherit properties and methods from other objects. Every JavaScript object has a prototype property, which refers to another object. When a property or method is accessed on an object, if it doesn't exist on that object, JavaScript looks up the prototype chain to find it. function Student(name, grade) {     Person.call(this, name);     this.grade = grade; } Student.prototype = Object.create(Person.prototype); Student.prototype.constructor = Student; Student.prototype.displayGrade = function() {     return this.name + " is in grade " + this.grade; }; let student1 = new Student("Bob", 10); console.log(student1.greet()); // Output: "Hello, my name is Bob" console.log(student1.displayGrade()); // Output: "Bob is in grade 10" 2)thread pool: Thread Pool : The thread pool in Node.js consists of a pool of worker threads (implemented using libuv). These worker...

 1)REbase and cherrypick 2)In mongodb _id if string than aggreagtion works or not? __v version can we change. size of id 3)isNaN-> valid ip address questions 4)dblookup in mongodb 5)ACID properties in sql 6)let x;  loop{ var x=100; } is allowed 7)tdd vs behavioural  8)Licenceing of npm package. Things to check for package selction 9)