bool

ES Module

// tree-shakeable import
import { bool } from 'chance'

// returns either `true` or `false` with a 50/50 likelihood
bool()
// returns either `true` or `false` with a 30/70 likelihood
bool({ likelihood: 30 })

Return a random boolean value (true or false).

bool();
=> true

The default likelihood of success (returning true) is 50%. Can optionally specify the likelihood in percent:

bool({likelihood: 30});
=> false

In this case only a 30% likelihood of true, and a 70% likelihood of false.

Class Instantiation

Alternatively, you can create an instance of a Chance class and call the bool method. This approach avoids instantiating a new PRNG instance on every function call.

// import the Chance class
import { Chance } from 'chance'

const chance = new Chance('my-random-seed')

// returns either `true` or `false` with a 50/50 likelihood
chance.bool()
// returns either `true` or `false` with a 30/70 likelihood
chance.bool({ likelihood: 30 })