We convert a Number to Boolean by using the JavaScript Boolean() method and double NOT operator(!!). A JavaScript boolean results in one of two values i.e. true or false. However, if one wants to convert a variable that stores integer “0” or “1” into Boolean Value i.e. “false” or “true”.
Approach 1: Boolean() method: Boolean function returns the boolean value of the variable. It can also be used to find the boolean result of a condition, expression, etc
Syntax:
Boolean(variable/expression)
Example: This example converts a number into a boolean.
HTML
<!DOCTYPE html><html><body> <center> <h1 style="color:green"> neveropen </h1> <h4> Click the button to change the number value into boolean. </h4> <button onclick="myFunction()">Change</button> <p>The number value of the variable is :</p> <p id="result"></p> <script> // Initializing boolvalue as true var numvalue = 1; // JavaScript program to illustrate boolean // conversion using ternary operator function myFunction() { document.getElementById("result") .innerHTML = Boolean(numvalue); } </script> </center></body></html> |
Note: If the above Boolean() method is called as Boolean(!numvalue), it shows the result as “false“. Similarly, if it is called Boolean(!!numvalue), it gives the result as “true“.
Output:
Approach 2: Using double NOT(!!) operator: This operator converts numbers with the value of zero to false and all other numbers to true.
Example: In this example, we will use the double NOT operator to convert the number into a boolean value.
HTML
<!DOCTYPE html><html><body> <center> <h1 style="color:green"> neveropen </h1> <h4> Click the button to change the number value into boolean. </h4> <button onclick="myFunction()">Change</button> <p>The number value of the variable is :</p> <p id="result"></p> <script> // Initializing boolvalue as true var numvalue = (!!1) // JavaScript program to illustrate boolean // conversion using ternary operator function myFunction() { document.getElementById("result") .innerHTML = (numvalue); } </script> </center></body></html> |
Output:
