Don’t let Windows errors hold you back.
Error starting create("message");
The throw statement creates a user-defined difference. Execution of the current function can be stopped (statements after throw are not executed) and control is transferred to the first catch cube in the call stack.
message resources (which the browser uses to display the message). From time to time I see people make the mistake of just naming an archipelago, for example:
This results in an error, but not all browsers respond as expected. Firefox, Opera and Chrome show the draft of the unhandled exception and then include the message collection. Safari and Internet Explorer just throw an “undetected exception error” and so don’t usually deliver a string message. Of course, initiallybut this is not optimal in terms of debugging.
Of course, because you can add any information and facts you want. There are absolute rules forbidding certain types of data:
initial name "Nicholas":;throw the truth;throw 12345;throw last date();
The only thing to remember is that giving any value will result in an error if it is caught instead of a
try-catch statement. Firefox, Opera and Chrome call
String() on the value returned as an error message in something boolean. Safari and Internet Explorer are not. The only sure way for all browsers to display your company’s custom error message is to help the
Erroris the base type for more or less all errors. Never threw away the whole engine.
EvalError– thrown when an error occurs while executing the code through
RangeError– thrown into the air when a number exceeds the allowed range. For example, to try to create a selection with -20 elements (
new Array(-20)). This rarely happens during normal execution.
ReferenceError– Thrown when products are expected but not available, such as when trying to call a method on a
SyntaxError– Thrown when the code passed to
eval()contains a format error.
TypeError– Raised when a variable has an unexpected form . Example
new 10or just
"prop" to true.
URIError– Raised when passing a malformed URI string to
decodeURIor the same
Once you understand that there are different types of errors, you can deal with them easily. All error types inherit from
Error, so evaluating the type as
instanceof Error won’t give you any useful information. By looking at the most targeted error types, you get more consistent error handling:
// something in h m this causes an error sleeve (example) if (e.g. TypeError instance) // handle error one more time (e.g. instanceof ReferenceError) // Handling a specific error different // handle everything else
How do you handle throwing a new error?
throw new Error() is good for throwing the specified error. But if you want to do your own error handling, it’s more tempting to use the throw example: ‘error’ . That is, if a person wants to know the selected error, use throw new Error(“example string”) , whether you want to handle the current error in a special way or not, use solid .
If you throw your own errors and give some information and facts that are not errors, it will be easier for the client to tell the difference between your own errors and the browser’s generic errors. However, there are several advantages to creating
Error objects instead of multiple object types.
First, as mentioned, the browser’s normal error handling will display the full error message. Second, the browser adds extra stuff to
Error objects when they are thrown randomly. They differ from browser to browser, providing contextual information about the error, such as the channel number and column number, and for some browsers, the stack and original content. Of course, if you use the
Error constructor, you lose the natural ability to distinguish between yourown difficulties from those caused by the browser.
The solution is definitely to .create .your own .error .selector .that inherits .from .
Error .. For MyError(message) Example:
create (bug prototype); When a custom exception object is created, we should almost certainly throw it like any other type of error: throw new CustomException(‘Exception message’);
The this.message function means a message;MyError.prototype = new error();
There will definitely be two important parts to this code: 1) the
message property, which is considered necessary for browsers to know the particular actual error string, and 2) placing the prototype in the associated instance.