Author: Michal Szymanski
A JavaScript Boolean represents one of two values: true or false.
Boolean Values
Very often, in programming, you will need a data type that can only have one of two values, like
- YES / NO
- ON / OFF
- TRUE / FALSE
For this, JavaScript has a Boolean data type. It can only take the values true or false.
The Boolean() Function
You can use the Boolean() function to find out if an expression (or a variable) is
true:
Boolean(10 > 9) // returns true
Or even easier:
(10 > 9) // also returns true
10 > 9 // also returns true
Everything With a "Value" is True
var b1 = Boolean(100); // Returns true
var b2 = Boolean(3.14); // Returns true
var b3 = Boolean(-15); // Returns true
var b4 = Boolean("Hello"); // Returns true
var b5 = Boolean('false'); // Returns true
var b6 = Boolean(1 + 7 + 3.14); // Returns true
Everything Without a "Value" is False
var b7 = Boolean(0); // Returns false
var b8 = Boolean(-0); // Returns false
var b9 = Boolean(""); // Returns false
var b10 = Boolean(); // Returns false
var b11 = Boolean(null); // Returns false
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