Random strings are used for various purposes in software development. For example, they can be used to code user IDs, generate passwords, and construct tokens in applications. If you’re developing a JavaScript-based program that needs random strings — or any other type of pseudo-random data — then this article is for you! You see, generating random characters (or strings) is easy with the right tools and techniques. Luckily, this article covers exactly that. Let’s get started…
Why do we need random strings?
Random strings are used to construct tokens, user IDs, and passwords in software. Let’s say you want to build a login system for a web application. You need to assign each user a unique login ID to allow them to log in. You can create a random string of characters to act as the user ID. The same applies to user tokens, which are used by various systems. Random strings are also useful for generating sales. Salt is a random string that’s used to add additional security to login systems. It makes it harder for hackers to brute force or log in to your system as they have to guess a unique salt for each user.
Ways to generate random strings in JavaScript
This section discusses four methods that allow you to generate a random string in JavaScript.
- Using a custom method.
- Using Math.random() method.
- Using crypto.getRandomValues() method .
- Using URNG library.
Let’s discuss each method in detail:
1. Using a Custom Method
You can create a custom method to generate a random string. Here we defined the words, numbers, and special characters. You can call this javascript function any time to generate a random string
function genRandonString(length) {
var chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$%^&*()';
var charLength = chars.length;
var result = '';
for ( var i = 0; i < length; i++ ) {
result += chars.charAt(Math.floor(Math.random() * charLength));
}
return result;
}
console.log(genRandonString(12));
2. Using Math.random() Method
The Math.random() method returns a pseudorandom number between 0 and 1. This method uses the current date and time as the source of entropy. In JavaScript, strings are represented by a sequence of characters between two double quotes (""). Since strings are just a sequence of characters, we can use the Math.random() method to generate a random string. Let’s look at a basic example where we construct a random string using the Math.random() method. Let’s write a JavaScript program that creates a string using the Math.random method.
var randomString = "";
randomString += Math.random();
randomString += Math.random();
randomString += Math.random();
console.log(randomString);
This program creates a random string and logs it to the JavaScript console. You can see in the screenshot below, the string is completely random.
Using crypto.getRandomValues() Method
The crypto.getRandomValues() method returns a pseudorandom sequence of bytes from a cryptographic random number generator. This method is a part of the JavaScript Crypto API. Let’s take a look at an example where we use the crypto.getRandomValues() method to generate a random string. Let’s write a JavaScript program that creates a string using the `crypto.getRandomValues` method.
var randomString = "";
randomString += crypto.getRandomValues(16).toString(16);
console.log(randomString);
In this program, we create a random string using the `crypto.getRandomValues()` method by passing 16 as the argument. Doing this instructs the method to return 16 random bytes. Let’s look at the output of this program in the screenshot below.
4. Using URNG Library
There are a few libraries available for generating random data in JavaScript. One such library is the Universal Random Number Generators (URNG) library. The library can be installed from npm or from NPM if you’re using JavaScript on the backend. Let’s take a look at an example where we use the URNG library to generate a random string. Let’s write a JavaScript program that creates a string using the URNG library.
var randomString = "";
randomString += URNG.generateRandomString(15);
console.log(randomString);
In this program, we create a random string using the URNG library by passing 15 as the argument. Doing this instructs the library to return 15 characters. Let’s look at the output of this program in the screenshot below.
Conclusion
In this article, we discussed why we need random strings and four different methods for generating them in JavaScript. Let’s summarize the tips discussed in this article. Firstly, remember that randomness is a state of uncertainty. In other words, it’s the lack of any consistent pattern. So, anything that is not predictable is considered random. Next, make sure that you’re not using Math.random() to generate non-random data. It is designed to generate a sequence of numbers that are unpredictable. So, don’t use it to generate numbers with a specific pattern. Finally, remember to implement a solution that generates non-repetitive random strings using a random data source. Doing this ensures that each string is unique and unpredictable.