JavaScript .EPSILON

The .EPSILON property is a static member of the Number object in JavaScript. It represents the smallest difference between 1 and the next larger floating-point number, making it useful for handling floating-point precision and comparison in JavaScript.

Syntax

Number.EPSILON;

Parameters:

• .EPSILON is a static constant and does not take any arguments.

Return value:

Returns a constant value representing the smallest difference between 1 and the next greater representable floating-point number. The exact value is approximately 2.220446049250313e-16.

Example

In this example, .EPSILON is used to check if two floating-point numbers are nearly equal by comparing the difference to a very small threshold:

function isEqual(a, b) {
  return Math.abs(a - b) < Number.EPSILON;
}

console.log(isEqual(0.1 + 0.2, 0.3));

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The output for this code is:

true

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In this example, .EPSILON is used as a threshold to handle floating-point precision issues. The function compares the absolute difference between two numbers and returns true if that difference is smaller than .EPSILON, treating them as effectively equal. This helps avoid unexpected results when comparing decimal values like 0.1 + 0.2 and 0.3.

Codebyte Example

This codebyte example checks if the total cost of items matches the expected amount, accounting for floating-point precision:

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The isEqual() function checks if two numbers are nearly equal using .EPSILON. This handles minor floating-point differences in the calculated total.