JavaScript - generate array with 10 random numbers

In this article, we would like to show you how to generate array with 10 random numbers in JavaScript.

Quick solution:

// ONLINE-RUNNER:browser;

const array = Array(10) // array size is 10
				.fill()
				.map(() => 50 * Math.random()); // numbers from 0-50 (exclusive)

console.log(array);

Note:

Use Math.floor() to get integers instead of float numbers. You can find practical examples in the sections below.

Using Array.fill() with map() method

In this example we take the following steps:

1. Create an array with size 10,
2. Use fill() method to fill the array with specified values,
3. use map() method to call Math.random() to generate a random value for each element in the array (from 0-50 exclusive).

Practical example:

// ONLINE-RUNNER:browser;

const array = Array(10) // array size is 10
				.fill()
				.map(() => 50 * Math.random()); // numbers from 0-50 (exclusive)

console.log(array);

If you want to receive integers instead of float numbers use Math.floor() method:

Practical example:

// ONLINE-RUNNER:browser;

const array = Array(10) // array size is 10
				.fill()
				.map(() => Math.floor(50 * Math.random())); // numbers from 0-50 (exclusive)

console.log(array);

Using Array.from() method (ES6+)

In this example, we use Array.from() method to create an array with size 10 and fill it with random numbers.

Practical example:

// ONLINE-RUNNER:browser;

// The solution for ES6+
const array = Array.from({ length: 10 }, () => Math.random() * 50);
console.log(array);

If you want to receive integers instead of float numbers use Math.floor() method:

Practical example:

// ONLINE-RUNNER:browser;

// The solution for ES6+
const array = Array.from({ length: 10 }, () => Math.floor(Math.random() * 50));
console.log(array);

Using crypto object

In this example, you can find solution that lets to randomize arrays using embedded crypto object.

Source code:

// ONLINE-RUNNER:browser;

const randomArray = (length, constructor = Uint32Array) => {
    const array = new constructor(length);
    return crypto.getRandomValues(array);
};


// Usage example:

console.log(randomArray(5, Uint8Array));      // also: Int8Array
console.log(randomArray(5, Uint16Array));     // also: Int16Array
console.log(randomArray(5, Uint32Array));     // also: Int32Array
console.log(randomArray(5, BigUint64Array));  // also: BigInt64Array

Note: the solution was intruduced in major web browsers in 2011-2014. 

References

1. Array.prototype.fill() - JavaScript | MDN 
2. Array.prototype.map() - JavaScript | MDN
3. Math.random() - JavaScript | MDN
4. Math.floor() - JavaScript | MDN