Generate Random Boolean in JavaScript

Generate Random Boolean in JavaScript

  1. Use Math.random() to Generate Random Boolean in JavaScript
  2. Use Array to Generate Random Boolean in JavaScript
  3. Use the _.sample(collection) Method to Generate Random Boolean in JavaScript

This article introduces how to generate random Boolean in JavaScript using Math.random(), Arrays, and _.sample(collection) function of lodash. The Math.random() function returns the numbers between 0 and 1 where 0 is inclusive while 1 is exclusive.

The _.sample(collection) method accepts a collection and returns one value randomly from the provided collection.

To use the _.sample(collection) method of lodash, add the following line of code in the <head> element.

<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.10/lodash.min.js"></script>

Use Math.random() to Generate Random Boolean in JavaScript

The Math.random() returns any number in the range of [0,1) where 0 is inclusive, but 1 is exclusive.

We can split this range into two partitions. First partition ranges from [0,0.5) and second from [0.5,1).

Why are we doing this? Because we are giving an equal chance of occurrence to true and false. If it is less than 0.5, then true; otherwise, the Boolean value would be false.

Example:

var random_boolean_value = Math.random() < 0.5;
console.log(random_boolean_value)

Output:

false

Let’s write a more detailed code to see that it returns true if less than 0.5.

See the following snippet.

for(var i=0 ; i < 10 ; i++){
 	var rand_number = Math.random();
 	console.log(rand_number);
 	var random_boolean_value = rand_number < 0.5;
 	console.log(random_boolean_value);
}

Output:

0.06464303463834886
true
0.27911502950509837
true
0.9811371177556913
false
0.539086724802587
false
0.3440647317306955
true
0.8779878853066467
false
0.2889025142115962
true
0.6346333079296975
false
0.28944321051370525
true
0.35970422088985354
true

Use Array to Generate Random Boolean in JavaScript

Let’s learn a more optimized version to generate random Boolean in JavaScript.

Check the following instance where we use Math.random() to produce a random value, multiplied by Array.prototype.length. Then, use the Math.floor() method to round off the nearest whole number.

Example:

const sample = arr => arr[Math.floor(Math.random() * arr.length)];
console.log(sample([true,false]));

Output:

true

Use the _.sample(collection) Method to Generate Random Boolean in JavaScript

Example:

<html>
	<head>
		<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.10/lodash.min.js"></script>
	</head>
	<body>
		<script>
    		console.log(_.sample([true, false]));
		</script>
	</body>
</html>

Output:

false
Mehvish Ashiq avatar Mehvish Ashiq avatar

Mehvish Ashiq is a former Java Programmer and a Data Science enthusiast who leverages her expertise to help others to learn and grow by creating interesting, useful, and reader-friendly content in Computer Programming, Data Science, and Technology.

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