JS: Boolean Constructor

Boolean(arg)

Force arg to Primitive Value true or false, return it.

console.log(Boolean(0) === false)
console.log(Boolean(0.0) === false)
console.log(Boolean(0.) === false)
console.log(Boolean(.0) === false)

console.log(Boolean("") === false)

console.log(Boolean(null) === false)
console.log(Boolean(undefined) === false)
console.log(Boolean(NaN) === false)

// anything else is true
console.log(Boolean(1))
console.log(Boolean(-1))
console.log(Boolean(Infinity))
console.log(Boolean({}))
console.log(Boolean([]))
console.log(Boolean(function () {}))

// Boolean called as a function, returns true/false primitive value
console.log((typeof Boolean(3)) === "boolean")

new Boolean(arg)

Convert arg to a value that's a boolean object type, return it.

let xx = new Boolean(2)

console.log((typeof xx) === "object")
console.log(xx.valueOf() === true)