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I'm trying to create an extendable error class in CoffeeScript with this code:
class @ExtendableError extends Error
constructor: (message = '') ->
super message
Object.defineProperty @, 'message',
configurable: true
enumerable : false
value : message
writable : true
Object.defineProperty @, 'name',
configurable: true
enumerable : false
value : @.constructor.name
writable : true
Object.defineProperty @, 'stack',
configurable: true
enumerable : false
value : (new Error(message)).stack
writable : true
When I try to throw one of these errors in Firefox using this code:
throw new ExtendableError('An error message');
I only get [object Object] printed to the console.
When I throw a built in error:
throw new Error('An error message');
I get the desired error message printed to the console: Error: An error message.
It should be noted that both, Error.toString() and ExtendableError.toString() work correctly. So I have absolutely no clue what's going on.
I tested the same code in Chrome without problems and I've literally searched for ours in Google without luck.
Any ideas?
Someone asked me to include the generated JavaScript code. So here it is:
// Generated by CoffeeScript 1.10.0
(function() {
var extend = function(child, parent) { for (var key in parent) { if (hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; },
hasProp = {}.hasOwnProperty;
this.ExtendableError = (function(superClass) {
extend(ExtendableError, superClass);
function ExtendableError(message) {
if (message == null) {
message = '';
}
ExtendableError.__super__.constructor.call(this, message);
Object.defineProperty(this, 'message', {
configurable: true,
enumerable: false,
value: message,
writable: true
});
Object.defineProperty(this, 'name', {
configurable: true,
enumerable: false,
value: this.constructor.name,
writable: true
});
Object.defineProperty(this, 'stack', {
configurable: true,
enumerable: false,
value: (new Error(message)).stack,
writable: true
});
}
return ExtendableError;
})(Error);
}).call(this);
523
asked Dec 18 '25 05:12
I put your file in lib/Error.coffee. Then I converted to Javascript:
coffee --compile --output dist lib
It created the file dist/Error.js.
Then I ran your code with this simple page:
<!DOCTYPE html>
<html>
<body>
<script src="dist/Error.js"></script>
<script>
throw new ExtendableError('example error');
</script>
</body>
</html>
I did some test with Firefox 46.0.1 in Linux and I didn't find any problem, look my screenshoots:
It very similar in Chrome.
I guess the problem is in another part of your code, maybe you're catching the exception and you're doing something with it.
If the problem persist in your Firefox installation and your think it is related with the version of the browser, you can use BrowserStack to test your code with many different versions of the browser and many different Operative System.
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