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Learn javascript Boolean Object Basics


Boolean objects vs primitive types

These are objects which represent true or false boolean primitive values only. Do not confuse with true and false values. these are boolean primitive types. Both are serving a different purpose.

Syntax

new Boolean(optional value)

optional value is optional which contains default value if the first parameter to the Boolean object is empty,0, NaN, Undefined, null, false, Boolean object has an initial value of false. If the Boolean object has parameter values like ‘false’, any object, Boolean holds true value.

Different ways to create a boolean falsy value

the below objects returns false values

  
var emptyBoolean = new Boolean();  
var zeroBoolean = new Boolean(0);  
var nullBoolean = new Boolean(null);  
var emptyString = new Boolean('');  
var undefinedBoolean = new Boolean(undefined);  
var nanBoolean = new Boolean(NaN);  
var falseBoolean = new Boolean(false);  

Different ways to create Boolean object truthy values

The below objects returns true values

  
var falseStringBoolean = new Boolean('false');  
var trueBoolean = new Boolean(true);  
var zeroBoolean = new Boolean('stringa');  
var zeroBoolean = new Boolean({});  
var zeroBoolean = new Boolean(0);

Boolean Object Methods Boolean object inherit from Boolean.prototype() which inherit from Object.prototype() global object. all global methods will be available Boolean toString method which converts to String format

  
true.toString(); // returns true  
false.toString(); // returns false  

**valueOf() method ** this method returns primitive value of Boolean object

  
boolObject = new Boolean();  
console.log(booleObject.valueOf()); // returns false  

Convert string boolean to Boolean in javascript

Many ways we can convert to boolean, one way is to use Json.parse() method

JSON.parse('true') - returns boolean true  
JSON.parse('false') -  returns boolean false  
Boolean(1).toString(); // true  
Boolean(0).toString(); // false  
var boolVal = Boolean("false");  
var myBoolean = Boolean.parse(boolString);  

Difference between the Boolean object and boolean primitive type

The boolean data type has only valued true or false. Boolean Object is like any other object new Boolean(true), new Boolean(false)

  
var booleanPrimitve= true;  
var otherBooleanPrimitve= true;  
var booleanObj = new Boolean(true);  
var otherBooleanObj= new Boolean(true);  
console.log(booleanPrimitve== otherBooleanPrimitve); // returns true, as both values are equal  
console.log(booleanObj == otherBooleanObj); // returns false - both are different objects  

How to convert Boolean to Number in javascript

Number object has a constructor which takes boolean values, we can easily convert boolean to Number

console.log(Number(true)); // returns 1  
console.log(Number(false)); // returns 0  
console.log(Number('true')); // returns NaN as we are passing strings  
console.log(Number('false'));  // returns NaN as we are passing strings  

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