--description--

Let’s assume you have written the following code:

const a = "Hello";
const b = "World";

console.log(c);

This code will run, but it will generate an error. In technical terms, this is called <dfn>throwing</dfn> an error. The first part of an error displays the type of error. This provides the first clue as to what you're dealing with. You'll learn more about the different error types later in the lesson. In this example, you have a ReferenceError.

A ReferenceError is thrown when one refers to a variable that is not declared and/or initialized within the current scope. In our case, the error message explains that the error has occurred because c is not defined.

Different errors of this type have different messages based on what is causing the ReferenceError. For example, another message you may run into is ReferenceError: can't access lexical declaration 'X' before initialization.

The next part of an error gives us the name of the file in which you can find the error (in this case, our script.js), and also the line number.

This allows you to easily navigate to the problematic line in your code. Here, the error originates from the fourth line of script.js, which is displayed as a link under the error message with the text at script.js:4. If you click this link, most browsers will navigate to the exact line of code and the rest of your script in the Sources tab of the Developer Tools.

Sometimes your browser’s console will also display the column (or character) in the line at which the error is occurring. In our example, this would be at script.js:4:13.

--questions--

--text--

What does the ReferenceError in the provided JavaScript code indicate?

--answers--

The variable used has been declared but used incorrectly in its type.

The variable called in the code has not been declared within the current scope.

The code has an issue with its syntax that prevents it from being parsed correctly.

The variable used has been declared but not initialized within the current scope.

--video-solution--

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