Differences between let, var and const

The differences between var, let, and const variable declaration in JavaScript include: Variables declared with var and const are scoped to the immediate function body. Variables declared with the var keyword are hoisted. Hoisting means that the variable can be accessed in their enclosing scope even before they are declared. Variables declared with the let keyword are block-scoped, which means the variables will have scope to the immediate enclosing block.The const keyword follows the same rules as the let keyword. The only difference with const is that const is used to define only constant values in JavaScript programs.

Difference between regular functions and arrow functions

Regular functions created using function declarations or expressions are ‘constructible’ and ‘callable’. Since regular functions are constructible, they can be called using the ‘new’ keyword. However, the arrow functions are only ‘callable’ and not constructible.

Usage of template literals

Template literals are literals delimited with backtick (`) characters, allowing for multi-line strings, for string interpolation with embedded expressions, and for special constructs called tagged templates. Template literals are sometimes informally called template strings, because they are used most commonly for string interpolation (to create strings by doing substitution of placeholders). However, a tagged template literal may not result in a string; it can be used with a custom tag function to perform whatever operations you want on the different parts of the template literal. It provides an easy way to create multiline strings and perform string interpolation.

Usage of map, filter, foreach, find functions

• The map() method creates a new array populated with the results of calling a provided function on every element in the calling array.
• The filter() method creates a shallow copy of a portion of a given array, filtered down to just the elements from the given array that pass the test implemented by the provided function.
• The forEach() method executes a provided function once for each array element.
• The find() method returns the first element in the provided array that satisfies the provided testing function. If no values satisfy the testing function, undefined is returned.