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How to find the Absolute Value in Javascript

You likely want to at some point find the absolute value of a number in Javascript. What is the absolute value you ask?

The absolute value of a number is its distance from zero on the number line, regardless of whether the number is positive or negative. In other words, it is always a non-negative value.

The absolute value concept is widely used in math and programming, and various fields of science to represent magnitudes without considering direction.

Below are three different ways to compute the absolute value of a number in JavaScript.

Method 1: Using the Built-In Math.abs() Function

The Math.abs() function in JavaScript returns the absolute value of a number. This means it will always return a non-negative value, regardless of whether the input number is positive or negative. If the input is not a number, it returns NaN.

const number = -10;
const absoluteValue = Math.abs(number);
console.log(absoluteValue); // Outputs: 10

In this approach, the built-in Math.abs() function is used to directly compute the absolute value of a given number. This method is concise and efficient, as Math.abs() internally handles all necessary checks for whether the number is negative, zero, or positive, and returns its non-negative magnitude. It is the simplest and most commonly used method for obtaining the absolute value in JavaScript.

Method 2: Writing your own Custom Function with an if/else Statement

This is our DIY (Do it yourself) way!

function getAbsoluteValue(num) {
  if (num < 0) {
    return -num;
  } else {
    return num;
  }
}
console.log(getAbsoluteValue(-10)); // Outputs: 10

In this method, a custom function named getAbsoluteValue is defined to manually compute the absolute value. The function checks if the input number is less than zero; if it is, it multiplies the number by -1 to convert it to a positive value. If the number is zero or already positive, it returns the number as is. This explicit approach makes the logic clear and can be easily modified or extended for additional functionality if needed.

Method 3: Use the Square and Square Root Approach

This is a little bit of a mathy approach!

function absValueUsingSqrt(num) {
  return Math.sqrt(num * num);
}
console.log(absValueUsingSqrt(-10)); // Outputs: 10

This method computes the absolute value by first squaring the number, which always results in a non-negative value, and then taking the square root of that squared number. The mathematical operations of squaring and then taking the square root effectively remove any negative sign, yielding the absolute value of the original number. Although this approach is slightly more computationally intensive than using Math.abs(), it demonstrates an alternative way to achieve the same result using basic arithmetic operations.

What are the different applications of absolute value?

Here are numerous areas where you will need to calculate the absolute value.

In data analysis and statistics, absolute values are used to compute deviations and errors, focusing solely on the magnitude regardless of direction.

In geometry and computer graphics, the absolute difference between coordinates is often used to calculate distances between points.

In financial calculations, absolute values help determine the magnitude of profit or loss without concern for whether the value is positive or negative.

In physics, absolute values are crucial for determining scalar quantities such as speed from velocity.

In machine learning, absolute values are used in computing metrics like Euclidean distance, which is essential for tasks such as clustering and classification.

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How to find the Absolute Value in Javascript

Method 1: Using the Built-In Math.abs() Function

Method 2: Writing your own Custom Function with an if/else Statement

Method 3: Use the Square and Square Root Approach

What are the different applications of absolute value?

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