Boolean

In computer science, a boolean is a logical data type that can have only the values true or false. A boolean is how a programming language lets you represent true and false. Without the ability to represent the boolean values a number of things in a language would no longer work. For example, in JavaScript, an if statement's conditional has to resolve to a boolean value for it to execute at all.  In a JavaScript for loop without it's boolean conditional the loop would never know whether to run it's coding or not. 

***JavaScript if Statement***
if(boolean conditional) {
   //coding
}

if(true) {
  console.log("boolean conditional resolved to true");
} else {
    console.log("boolean conditional resolved to false");
  }



***JavaScript for Loop***
for(control variable; boolean conditional; counter) {
  //coding
}

for(var i=0; i<4; i++) {
  console.log("I print only when the boolean conditional is true");
}

Learn more

General knowledge

• Boolean on Wikipedia

Technical reference

• The JavaScript global object: Boolean
• JavaScript data types and data structures