A Journey Into JavaScript (III)

medini_1024169437

Introduction: This is the third article in the new series about the nice parts of Java Script. Its about different ways to access variables:

// 1. undefined values cannot be easily accessed in JS 

// this would cause: "ReferenceError: "unknownVariable" is not defined
// if (!unknownVariable) {
// console.log("No value");
// }

// 2. but we can use "in"
if ("unknownVariable" in this) {
	console.log("The variable 'unknownVariable' exists in the current scope - don't know the value though");
}

// 3. combined
if (!"unknownVariable" in this || !this["unknownVariable"]) {
	console.log("No value");
}