JavaScript Data Types Mocktest

In JavaScript, there is no specific data type called Integer. Instead, numeric values, whether integers or floating-point numbers, are represented using the Number data type.

The value 'John Doe' is a string of characters, so the data type of the variable name will be String in JavaScript.

The value true represents a boolean truth value in JavaScript, so its data type is Boolean.

The Undefined data type in JavaScript is used to represent the absence of a value, typically when a variable has been declared but not yet assigned a value.

Interestingly, the data type of the value null in JavaScript is Object, although it is technically a primitive value. This is considered a quirk of JavaScript.

In JavaScript, the String data type is used to represent textual data, which can be single characters or longer strings of characters.

The typeof operator in JavaScript returns the data type of a variable or expression. In this case, typeof undefined will return the string 'undefined', indicating that undefined is a data type in JavaScript.

In JavaScript, double forward slashes // are used to start a single-line comment. Anything after // on the same line is treated as a comment and is not executed by the JavaScript engine.

The value NaN stands for "Not a Number" and is a specific numeric value in JavaScript. Its data type is Number, although it represents an invalid or undefined numeric value.

The Symbol data type in JavaScript is used to represent a unique identifier, particularly useful for creating non-colliding property keys in objects or for defining unique constants.