JS: Boolean.prototype

Boolean.prototype is the value of the property key "prototype" of the function Boolean.

[see JS: Boolean Object]

console.log( Boolean.hasOwnProperty ( "prototype" ) ); // true

Type

Type of Boolean.prototype is object.

[see JS: Value Types]

// type of Boolean.prototype
console.log ( typeof Boolean.prototype === "object" ); // true
console.log ( Object.prototype.toString.call( Boolean.prototype ) === "[object Boolean]" ) // true

Parent

Parent of Boolean.prototype is Object.prototype.

// parent of Boolean.prototype
console.log ( Object.getPrototypeOf ( Boolean.prototype ) === Object.prototype ); // true

[see JS: Prototype and Inheritance]

Purpose

Purpose of Boolean.prototype is to hold methods valueOf and toString for converting values to true or false, or a string form.

Properties

1. Boolean.prototype.constructor
2. Boolean.prototype.valueOf
3. Boolean.prototype.toString

Boolean.prototype.constructor

Value is Boolean.

console.log ( Boolean.prototype.constructor === Boolean ); // true

Boolean.prototype.valueOf

Boolean.prototype.toString () → converts the this binding to true or false.

console.log ( true.valueOf () === true ); // true
console.log ( false.valueOf () === false ); // true

Boolean.prototype.toString

Boolean.prototype.toString () → converts the this value to "true" or "false".

[see JS: “this” Binding]

console.log ( true.toString () === "true" ); // true
console.log ( false.toString () === "false" ); // true

Reference

ECMAScript® 2016 Language Specification#sec-boolean.prototype