JS: Boolean Object

Boolean is the value of the property key "Boolean" of the global object.

console.log( window["Boolean"] === Boolean ); // true

Boolean is a function.

〔►see JS: Data Types〕

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

The parent of Boolean is Function.prototype. 〔►see JS: Prototype and Inheritance〕

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

The purpose of Boolean is:

1. Implicitly called by JavaScript to convert value to true or false. e.g. in a if statement.
2. Implicitly called by JavaScript to convert true or false to string, by first converting the value to boolean object, then use method toString.
3. Has the property key "prototype" that holds valueOf and toString methods.

〔►see JS: true, false〕

Boolean Constructor

〔►see JS: Boolean Constructor〕

Properties

• Boolean.prototype

〔►see JS: Boolean.prototype〕

Reference

ECMAScript® 2016 Language Specification#sec-boolean-constructor