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steave
answered Jun 24 '23 00:00
Your approach to creating an isUndefined function in JavaScript is almost correct. However, there are a couple of things you need to consider:
The isUndefined function should check if the variable is undefined, not whether it has a truthy or falsy value. This is because variables with falsy values (such as false, 0, '', etc.) are still defined.
When returning a boolean value (true or false), it's best to use the return statement directly rather than the conditional statement.
Here's an updated version of the isUndefined function:
function isUndefined(gVar) {
return typeof gVar === 'undefined';
}
This function uses the typeof operator to check if the type of gVar is 'undefined'. If it is, it means the variable is undefined, and the function will return true. Otherwise, it will return false.
You can use this function to check if a variable is undefined and handle it accordingly in your code.
Example usage:
var myVar;
console.log(isUndefined(myVar)); // Output: true
var anotherVar = 123;
console.log(isUndefined(anotherVar)); // Output: false
By using this function, you can detect and handle undefined variables or objects early in your code to avoid potential errors or exceptions.