By default an object called with the new keyword returns 'this' jsmrcaga commented Apr 1, 2016 👍 chrismbeckett commented May 7, 2016 And here is a working snippet for use with Zakas and do not, in any way, reflect those of my employer, my colleagues, Wrox Publishing, O'Reilly Publishing, or anyone else. Lego Engineers. These occur rarely during normal execution. More about the author
For Node.js there is a small library that does this for you: npmjs.com/package/node-custom-errors –Lukasz Korzybski Jul 14 '15 at 8:17 add a comment| up vote 2 down vote I just had Reply to this Comment Ben Nadel Nov 4, 2015 at 8:22 AM 12,911 Comments @Tangxinfa,Very interesting - I had not seen that before, will have to look into it. Use SyntaxError instead. Is a world with two different types of air possible?
Es6 Custom Error
lol. Please enter your age before continuing:") if (isNaN(parseInt(agecheck))) throw new SyntaxError("Please enter a valid age") else if (agecheck<13) throw new RangeError("Sorry, but you are too young for this movie") alert("Enjoy the The syntax is: throw myerrorobject Where myerrorobject can in fact be anything from a string, number, Boolean, to a new or one of the 6 default Error Constructor functions. There are, however, several advantages to throwing actual Error objects instead of other object types.
Well-designed and well-tested errors will help you maintain projects, but also help users figure out what to do when things go wrong. Sign up for free to join this conversation on GitHub. Don't even augment it. https://gist.github.com/justmoon/15511f92e5216fa2624b slavafomin commented Sep 3, 2016 Thank you for this great Gist!
Node Custom Error
However, as mentioned in the comments, because that version sets prototype to new Error(), I could set NotImplementedError2.prototype.name = "NotImplementedError2" and be OK. So, for example, if we were to generate the stacktrace inside of an error Factory function, we could tell V8 to exclude the factory function when generating the stack. Each of the following properties can be optionally passed-in// as part of the Settings argument.// --// See CFThrow documentation: https://wikidocs.adobe.com/wiki/display/coldfusionen/cfthrowthis.type = ( settings.type || "Application" );this.message = ( settings.message || "An click site assert.strictEqual(err.stack.split('\n').indexOf('doSomethingBad'), 7); // The extra property should have been set assert.strictEqual(err.extra, 42); } // Spoiler: It passes!
If you later want to add a NotImplementedError.prototype.toString the object now aliases to Error.prototype.toString -- better to do NotImplementedError.prototype = new Error(). –cdleary Oct 1 '10 at 8:01 3 I Hide Newsletter Sign-up See also Standard built-in objectsErrorPropertiesError.prototypeError.prototype.columnNumberError.prototype.fileNameError.prototype.lineNumberError.prototype.messageError.prototype.nameError.prototype.stackMethodsError.prototype.toSource()Error.prototype.toString()Related pages:EvalErrorInternalErrorRangeErrorReferenceErrorSyntaxErrorTypeErrorURIErrorInheritance:FunctionProperties Function.arguments Function.arityFunction.callerFunction.displayNameFunction.lengthFunction.nameFunction.prototypeMethodsFunction.prototype.apply()Function.prototype.bind()Function.prototype.call()Function.prototype.isGenerator()Function.prototype.toSource()Function.prototype.toString()ObjectProperties Object.prototype.__count__ Object.prototype.__noSuchMethod__ Object.prototype.__parent__ Object.prototype.__proto__Object.prototype.constructorMethods Object.prototype.__defineGetter__() Object.prototype.__defineSetter__() Object.prototype.__lookupGetter__() Object.prototype.__lookupSetter__()Object.prototype.hasOwnProperty()Object.prototype.isPrototypeOf()Object.prototype.propertyIsEnumerable()Object.prototype.toLocaleString()Object.prototype.toSource()Object.prototype.toString()Object.prototype.unwatch()Object.prototype.valueOf()Object.prototype.watch()Object.setPrototypeOf() © 2005-2016 Mozilla Developer Network and individual contributors. Standard ECMAScript 2017 Draft (ECMA-262)The definition of 'Error' in that specification. Typescript Custom Error If you need additional methods/properties, you can add them to the object before returning it.
Tweet This Groovy post by @BenNadel - Creating Custom Error Objects In Node.js With Error.captureStackTrace() Thanks my man — you rock the party that rocks the body! hassansin commented Dec 21, 2015 How do you match the string representation of CustomError to that of Error object? When we run this code, I get the following console output:AppError: You are missing an argument.- at thatMethod (/..../nodejs/custom-errors/test.js:42:3)- at thisMethod (/..../nodejs/custom-errors/test.js:56:2)- at Object.