Custamizable Error Messages Javascript
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Custom Error Messages Rails
Add-ons Firefox WebExtensions Developer ToolsFeedback Get Firefox help Get web development help Join the MDN community customize devise error messages Report a content problem Report a bug Search Search Languages Català (ca) Deutsch (de) Español (es) Français (fr) 日本語 (ja) Polski (pl) Русский (ru) 中文 (简体) laravel custom error messages (zh-CN) Add a translation Edit Advanced Advanced History Print this article MDN Web technology For developers JavaScript JavaScript reference Standard built-in objects Error Error.prototype.message Your Search Results fscholz Mingun Sheppy evilpie Sevenspade Waldo Error.prototype.message In This Article DescriptionExamplesThrowing a custom errorSpecificationsBrowser compatibilitySee also The message property is a human-readable description of the error.
Grails Custom Error Messages
Description This property contains a brief description of the error if one is available or has been set. SpiderMonkey makes extensive use of the message property for exceptions. The message property combined with the name property is used by the Error.prototype.toString() method to create a string representation of the Error. By default, the message property is an empty string, but this behavior can be overridden for an instance by specifying a message as the first argument to the Error constructor. Examples Throwing a custom error var e = new Error('Could not parse input'); // e.message is 'Could not parse input' throw e; Specifications Specification Status Comment ECMAScript 1st Edition (ECMA-262) Standard Initial definition. ECMAScript 5.1 (ECMA-262)The definition of 'Error.prototype.message' in that specification. Standard ECMAScript 2015 (6th Edition, ECMA-262)The definition of 'Error.prototype.message' in that specification. Standard ECMAScript 2017 Draft (ECMA-262)The definition of 'Error.prototype.message' in that specification. Draft Browser compatibility Desktop Mobile Feature Chrome Firefox (Gecko) Internet Explo
I got a lot of responses and follow-up questions, so I thought I'd continue the discussion by explaining a little more about how to throw your own errors. To review, the basic javascript error object syntax is: throw new Error("message"); This works in all browsers and will display the error es6 custom error information in the same way it would any unintentional JavaScript error. The "message" string is stored in the message property of the
Javascript Custom Error Es6
object (which is what the browser uses to display the message). Periodically, I see people throwing errors by just providing the string, such as this: throw "message"; Doing so will cause an error to be thrown, but https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/message not all browsers respond the way you'd expect. Firefox, Opera, and Chrome each display an "uncaught exception" message and then include the message string. Safari and Internet Explorer simply throw an "uncaught exception" error and don't provide the message string at all. Clearly, this is suboptimal from a debugging point of view. Of course, you can throw any type of data that you'd like. There are no rules prohibiting specific data types: throw https://www.nczonline.net/blog/2009/03/10/the-art-of-throwing-javascript-errors-part-2/ { name: "Nicholas" }; throw true; throw 12345; throw new Date(); The only thing to remember is that throwing any value will result in an error if it's not caught via a try-catch statement. Firefox, Opera, and Chrome all call String() on the value that was thrown to display something logical as the error message; Safari and Internet Explorer do not. The only surefire way to have all browsers display your custom error message is to use an Error object. ECMA-262, 3rd Edition actually specifies seven error object types. These are used by the JavaScript engine when various error conditions occur and can also be manually created: Error - base type for all errors. Never actually thrown by the engine. EvalError - thrown when an error occurs during execution of code via eval() RangeError - thrown when a number is outside the bounds of its range. For example, trying to create an array with -20 items (new Array(-20)). These occur rarely during normal execution. ReferenceError - thrown when an object is expected but not available, for instance, trying to call a method on a null reference. SyntaxError - thrown when the code passed into eval() has a syntax error. TypeError - thrown when a variable is of an unexpected type. For example, new 10 or "prop" in true. URIE
gist now Instantly share code, notes, and snippets. Star 151 Fork 22 justmoon/custom-error.js https://gist.github.com/justmoon/15511f92e5216fa2624b forked from subfuzion/error.md Last active Sep 29, 2016 Embed What would you like to do? Embed Embed this gist in your website. Embed Share Copy sharable URL for this gist. Share Clone via HTTPS Clone with Git or checkout with SVN using the repository's web address. HTTPS Learn more about clone URLs error messages Download ZIP Code Revisions 7 Stars 151 Forks 22 Creating custom Error classes in Node.js Raw custom-error.js 'use strict'; module.exports = function CustomError(message, extra) { Error.captureStackTrace(this, this.constructor); this.name = this.constructor.name; this.message = message; this.extra = extra; }; require('util').inherits(module.exports, Error); Raw error.md It's nice to be able to distinguish error types by classes. But custom error messages it's a bit tricky to correctly create a custom error class in Node.js, so here is an example. The example also shows how to add an extra parameter called extra that will be stored as a property on the error. Usage var CustomError = require('./errors/custom-error'); function doSomethingBad() { throw new CustomError('It went bad!', 42); } Features Name appears once - less editing if you have to create lots of custom error classes Easy to subclass - just change the last line to inherit from another custom error class you created Correct stack trace - no extra stack frames, no double capturing of the stack trace Anti-patterns These are some things that I've seen in other proposed solutions that you should avoid. Error.call(this) - creates another error object (wasting a bunch of time) and doesn't touch this at all Error.captureStackTrace(this, arguments.callee); - works, but arguments.callee is deprecated, so don't use it this.stack = (new Error).stack - thi