JavaScript Math.random: How to Generate Random Number

To generate a random number in JavaScript, use the Math.random() function. JavaScript provides a Math module that supports all type of mathematical functions that helps us carry out complex math calculation.

JavaScript Math.random

The Math.random() is a built-in JavaScript method that returns a random number between 0 (inclusive) and 1 (exclusive). The Math.random() function does not accept any argument and returns the value between 0 to 1, in which 1 is exclusive, and 0 is inclusive.

Syntax

Math.random()

Parameters

It does not accept any argument.

Return Value

The Math.random() function returns the floating point, a pseudo-random number between 0 (inclusive) and 1 (exclusive).

Example

// app.js

console.log(Math.random());

Output

Javascript Math Random Tutorial

The Math.random() does not provide cryptographically secure random numbers. Therefore, do not use them for anything related to security.

Getting a random number between two values

The Math.random() method explicitly does not provide the arguments that can return the values between two numbers. However, we can create a method that can do this for you.

// app.js

const app = (min, max) => {
   return Math.random() * (max - min) + min;
}

console.log(app(19, 25));

Output

Math.random() Example

All the random values will be generated between those two arguments. In the above example, all the values are generated in floating values. You can also generate integer values as well. See the following example.

// app.js

const app = (min, max) => {
   min = Math.ceil(min);
   max = Math.floor(max);
   return Math.floor(Math.random() * (max - min + 1)) + min;
}

console.log(app(19, 25));

Output

Getting a random integer between two values, inclusive

So, we have seen how we can use the Math.random() function to generate the random values in a float and an integer.

That’s it.

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