Also, take into account whether you’re applying for junior or more advanced developer positions. If you’re applying for more advanced developer positions, you should also understand more complex topics like closures, asynchronous programming, and object-oriented programming.
Top Questions and Answers
· Lightweight, interpreted language
· Complementary to and integrated with Java
Undefined means a variable has been declared but hasn’t yet been assigned a value. Null is an assignment value that represents no value or no object.
Developers use escape characters to represent certain special characters in a string. Examples of escape characters include \n for a new line and \t for a tab.
7. What does the Logical AND (&&) operator do?
The Logical AND (&&) operator returns true if both operands are true, and false if they’re not.
8. What is the difference between == and === operators?
The == operator compares the values of two operands, while the === operator compares both the values and the types of the operands.
The let keyword declares variables with block scope, whereas the var keyword declares variables with function scope.
A closure is a function that has access to variables in its outer scope, even after the outer function has returned.
Synchronous code executes in sequence, whereas asynchronous code executes out of order. Asynchronous code prevents blocking the main thread and improves performance.
Call and apply invoke a function with a specified this value and arguments. The difference is that call takes arguments as a comma-separated list, whereas apply takes arguments as an array.
Slice extracts a portion of an array. Splice adds or removes elements from an array.
The let keyword declares variables that can be reassigned, and the const keyword declares variables that can’t.
Both map and forEach iterate over an array. Map returns a new array with the results of calling a provided function on every element in the array, while forEach doesn’t return anything.
The async attribute loads a script asynchronously. That means that the script won’t block the rendering of the page. The defer attribute loads a script after the page has finished parsing. In that case, the script won’t block the rendering of the page and will execute in the order in which it appears in the HTML.
Get ready and build a successful career