Lecture 128:- Type of Operator

In JavaScript, the typeof operator is used to determine the type of a value or expression. The result of the typeof operator is a string that indicates the data type of the value or expression.

The syntax of the typeof operator is as follows:

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typeof operand

Here, operand can be any value or expression. The result of the typeof operator is a string that represents the type of operand.

The typeof operator can be used with the following types of operands:

• Undefined: If the operand is undefined, the result is the string "undefined".
• Null: If the operand is null, the result is the string "object". This is a historical quirk of JavaScript, and is not actually correct.
• Boolean: If the operand is a boolean value (true or false), the result is the string "boolean".
• Number: If the operand is a number, the result is the string "number".
• String: If the operand is a string, the result is the string "string".
• Symbol: If the operand is a symbol (introduced in ECMAScript 6), the result is the string "symbol".
• Object: If the operand is an object or function, the result is the string "object".

Here are some examples of using the typeof operator:

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typeof undefined  // "undefined" typeof null       // "object" typeof true       // "boolean" typeof 42         // "number" typeof "Hello"    // "string" typeof Symbol()   // "symbol" typeof {foo: 42}  // "object" typeof function(){} // “function”