medtigo Interview Questions and Answers

let, var, and const are JavaScript keywords used for declaring variables with different scopes and mutability.

• var is function-scoped and can be redeclared and reassigned

• let is block-scoped and can be reassigned but not redeclared

• const is block-scoped and cannot be reassigned or redeclared

• Use const for values that won't change, let for values that will, and var for legacy code or global variables

The $ sign in JQuery is a shorthand for the JQuery function.

• The $ sign is used to select elements in JQuery.

• It can also be used to create new elements.

• It is a shorthand for the JQuery function.

• Example: $('p') selects all the paragraphs on a page.

Hoisting is a JavaScript mechanism where variables and function declarations are moved to the top of their scope.

• Variables declared with var are hoisted to the top of their scope

• Function declarations are also hoisted to the top of their scope

• Function expressions are not hoisted

• Hoisting can lead to unexpected behavior and bugs

• Example: console.log(x); var x = 5; // Output: undefined

I rate myself 8/10 in Javascript and 7/10 in jQuery.

• Proficient in using vanilla Javascript to create dynamic and interactive web pages

• Experience in using jQuery to simplify DOM manipulation and event handling

• Familiarity with popular Javascript frameworks like React and Angular

• Continuously learning and improving my skills in Javascript and jQuery

Async, await, and promises are JavaScript features used for handling asynchronous operations.

• Promises are objects that represent the eventual completion or failure of an asynchronous operation.

• Async/await is a syntax for writing asynchronous code that looks like synchronous code.

• Async functions always return a promise.

• Await can only be used inside an async function and it waits for the promise to resolve or reject before continuing execution.

• Async/await is built on top of pro...read more

The difference between == and === is that == compares values while === compares both values and types.

• The == operator performs type coercion before comparing values.

• The === operator does not perform type coercion and compares both values and types.

• Using === is generally considered safer and more reliable.

• Example: 5 == '5' returns true, but 5 === '5' returns false.