Exploring the concept of for loops: utilizing variables without defined values within the loop

Alright, I've come across an issue with a simple for loop embedded within a function that requires an array as its sole parameter. The condition for the loop is set as array.length.

Within the loop, I'm utilizing an undefined variable along with a document.write.

The dilemma lies in the fact that Javascript terminates the loop after one iteration due to the unset status of variable y. I initially anticipated the loop to iterate through (array.length).

If you wish to delve into this further, check out the following CodePen: http://codepen.io/anon/pen/wmlBC (uncomment var y).

    function checkName(array){

    var i = 0;
    var y = "";

    for(i = 0; i < array.length; i++){

        y += array[i]

    }

    return y;


}

var arrayNames = ["liselore", "karel", "david", "stefan", "kevin", "sandy"];

console.log(checkName(arrayNames));

Answer №1

Upon inspecting the browser console, a JavaScript error is revealed:

ReferenceError: y is not defined

As a consequence of y not being defined, the loop halts as a result of the ReferenceError.

Answer №2

Your code is causing a ReferenceError. In JavaScript, Errors function similarly to Exceptions in other programming languages. They disrupt the normal program flow and rise up until they encounter a catch statement that matches their type.

If the Error goes unhandled, the engine will treat it as an Uncaught [error] and terminate the current event.

Answer №3

Every mistake proves to be fatal in the world of JavaScript (unless you manage to catch them, and even then it's not guaranteed).

As a result, the loop will come to a halt right away, regardless of whether there are any remaining iterations to complete.

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