Test string as a literal and as an object

The typeof operator in JavaScript is utilized to determine the data type of an expression and returns a string that identifies that data type. It serves to retrieve the data type, represented as a string, of its operand, which can encompass literals or data structures like variables, functions, or objects.

The operator provides insight into six potential values: "object," "boolean," "function," "number," "string," and "undefined," indicating the respective data types of the operand. This operator is invaluable for dynamically assessing the nature of data and making informed decisions in programming logic.

var strLtr = "This is a string literal"; var strObj = new String("This is a string object"); alert(isLtrObj(strLtr)); alert(isLtrObj(strObj)); function isLtrObj(str) { return typeof(str) == 'string' str instanceof String; }

JavaScript Literals

A literal in programming is a specific notation used to directly represent a constant or fixed value within the source code. Virtually all programming languages provide ways to express fundamental values such as integers, floating-point numbers, strings, booleans, and characters using literals. Additionally, some languages include notations for more complex values like those from enumerated types, as well as compound structures such as arrays, records, and objects. Literals serve as a convenient and direct means to declare unchanging values within the code, contributing to code readability and simplicity.

JavaScript Objects

An object in programming refers to an unordered collection of primitive data types and sometimes reference data types. It is organized as a sequence of name-value pairs, where each element is termed a property. Alongside properties, objects can also contain functions, which are known as methods. These properties and methods collectively encapsulate data and behavior within a single entity, enabling developers to model real-world entities and their interactions in software. Objects serve as a fundamental building block in object-oriented programming, facilitating the creation of more organized, modular, and efficient code.


To test a string as a literal, you can simply enclose it in quotes, like "example string". This treats the content as a raw string value. To test a string as an object, you would create a string object using the String constructor, such as new String("example string"). This treats the string as an instance of the String object with associated properties and methods.