# How to get a random boolean in JavaScript

July 19, 2020 (Updated September 2, 2021)

I was just doing a coding challenge on Codewars where I had to randomly set the characters of a given string to either uppercase or lowercase.

This required coming up with some means of *randomly *setting a character 's casing so a quick StackOverflow search gave me this nifty little trick:

`Math.random() >= 0.5`

This works because `Math.random()`

returns a random float between 0 and 1. So the probability of that random number being 0.5 or above is roughly 50%.

Here is my final solution to the challenge:

```
const randomCase = str => {
return str
.split('')
.map(char =>
Math.random() >= 0.5 ? char.toUpperCase() : char.toLowerCase()
)
.join('')
}
```

Tagged:
JavaScript