js-short-circuiting-booleans.js

// Function that accepts a boolean as first argument
// and returns the boolean otherwise `false`
const booleanOrFalse = value => (typeof value == 'boolean') && value;

// Function that accepts a boolean as first argument
// and returns the boolean otherwise `true`
const booleanOrTrue = value => (typeof value != 'boolean') || value;

console.log(booleanOrFalse(true)); // true
console.log(booleanOrFalse(false)); // false
console.log(booleanOrFalse(1)); // false
console.log(booleanOrFalse(0)); // false
console.log(booleanOrFalse('String')); // false
console.log(booleanOrFalse({})); // false
console.log(booleanOrFalse([])); // false

console.log(booleanOrTrue(true)); // true
console.log(booleanOrTrue(false)); // false
console.log(booleanOrTrue(1)); // true
console.log(booleanOrTrue(0)); // true
console.log(booleanOrTrue('String')); // true
console.log(booleanOrTrue({})); // true
console.log(booleanOrTrue([])); // true