What are exponential notation and NaN in JavaScript?

Understanding exponential notation and NaN (Not a Number) in JavaScript is key for handling numerical data effectively. Exponential notation simplifies the representation of large or small numbers, making code more readable. Knowing how to work with NaN helps us gracefully handle errors and unexpected values. Let’s discuss them one by one.

Exponential notation

In JavaScript, we can represent numbers in the form of exponential notation. It is used when we want to represent a large number or a very small number in scientific notation, which is basically multiplied by 1010 to the power of. For example, 6.022e23 is a number, which, in scientific notation, is 6.0226.022 multiplied by 1010 raised to the power of 2323, which is a valid and meaningful numerical representation. Instead of writing e we can also use capital E. Both produce the same result.

Let’s see some more examples of using exponential notation:

Code example

console.log(8e11);
console.log(8E11);
console.log(34e-4);
console.log(4.5E-6);

Explanation

  • Lines 1–2: The example 8e11 returns 88 multiplied by 1010 to the power of 1111, and 8E11 also produces the same result.

  • Lines 3–4: These examples show the usage of values using a negative index as a power.

    • 34e-4 returns 3434 multiplied by 1010 to the power of −4-4.

    • 4.5E-6 returns 4.54.5 multiplied by 1010 to the power of −6-6.

NaN

NaN is a specific error code that stands for Not a Number. It is used when an operation is tried, and the outcome is not numerical, such as when attempting to multiply a string by a number. NaN is often the result of invalid mathematical operations, such as dividing 00 by 00, or calculating the square root of a negative number, or attempting to parse a non-numeric string as a number.

Code example

console.log('hello' * 9);
console.log(0/0);
console.log(Math.sqrt(-16));
console.log(parseInt("Hello"));

Note: parseInt is used to convert number string ("123") into a numeric value.

Explanation

  • Line 1: It tries to multiply a string with a number, so it returns a NaN.

  • Line 2: It uses an invalid mathematical division, which also results in NaN.

  • Line 3: It tries to calculate the square root of a negative number, which results in NaN.

  • Line 4: It tries to parseInt a string into a numeric value, which results in NaN.

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