This tutorial will demonstrate the methods for converting string to boolean using JavaScript.
How to Convert/Transform a String Into Boolean Using JavaScript?
Use the following methods for converting a string into a boolean using JavaScript:
- Strict equality operator (===)
- Double not (!!) operator
- Boolean Object
Let’s see how these methods will work.
Method 1: Convert a String to Boolean Using Strict Equality (===) Operator
The “Strict equality” (===) Operator or the “identity” operator is utilized for converting a string to a boolean value. It verifies whether the left-hand side value becomes equal to the right-hand side value. If yes! it returns “true” else, it returns “false”.
Syntax
The syntax for the strict equality operator is as follows.:
Return value
Its outputs “true” if the compared values consist of the same value and type.
Example 1:
Create a variable named “string” that stores a boolean value “true” as a string:
Compare the string to the string “true” using the “Strict equality” (===) Operator. Only if the string is “true”, the output will be allocated a boolean value “true”:
Print the result on the console using the “console.log()” method:
Output
The output displays “true”, as the strict equality returns true when both operands are equal in terms of the type and value.
Example 2:
In variable “string”, store boolean value “false”:
Compare the string “false” with the string “true”:
Output
The output shows “false” because the strict equality operator returns true if the string is actually “true”.
Method 2: Convert a String to Boolean Using Double NOT (!!) Operator
To convert string to boolean, there is another method in JavaScript, known as a double exclamation (!!) that is a double NOT (!!) operator. It returns a boolean value by reversing the result of a single NOT operator.
Syntax
The syntax for the double NOT (!!) operator is as follows:
In the above syntax:
- The first (!) operator changes it to an inverted boolean value. The second (!) operator inverts the inverted boolean value. In other words, it is now the actual Boolean value of the object.
Example 1:
Create a variable “string” and store a boolean value “true” as a string in it:
Use the double NOT (!!) operator with string to convert into a boolean value:
Output
Output displays “true”, as in (!!) operator, first (!) converts “true” into “false”, then the second (!) again converts it into “true”.
Method 3: Convert a String to Boolean Using Boolean Object
For converting the string to a boolean, use the JavaScript built-in “Boolean” object. It is a wrapper object for boolean values.
Syntax
The syntax for converting string to boolean with the help of a Boolean object is as follows:
- It takes a string as an argument and returns a boolean value.
- It returns “true” if the passed string is not empty.
- For an empty string, it returns “false”.
Example 1:
Create a variable “string” and store a boolean value “true” as a string in it:
Call the Boolean wrapper by passing the string:
Output
The output returns a boolean value “true”, as the passed string is not empty.
Example 2:
Store the boolean value “false” in a variable “string”:
Invoke the Boolean wrapper by passing the string:
The corresponding output will be:
Conclusion
To convert a string to a boolean, use the “Strict equality” operator (===) that compares the specified string to the string “true” and it returns a boolean value “true” if the compared values are of the same type and value. The “Double not” (!!) operator returns a boolean value by reversing the result of a single NOT operator, or JavaScript “Boolean” Object that returns a boolean value “true” if the passed string is not an empty string else return “false”. This tutorial demonstrates the methods for converting string to boolean using JavaScript.
