\n\n## What is Check-Error?\n\nCheck-Error is a module which you can use to retrieve an Error's information such as its `message` or `constructor` name and also to check whether two Errors are compatible based on their messages, constructors or even instances.\n\n## Installation\n\n### Node.js\n\n`check-error` is available on [npm](http://npmjs.org). To install it, type:\n\n $ npm install check-error\n\n### Browsers\n\nYou can also use it within the browser; install via npm and use the `check-error.js` file found within the download. For example:\n\n```html\n\n```\n\n## Usage\n\nThe primary export of `check-error` is an object which has the following methods:\n\n* `compatibleInstance(err, errorLike)` - Checks if an error is compatible with another `errorLike` object. If `errorLike` is an error instance we do a strict comparison, otherwise we return `false` by default, because instances of objects can only be compatible if they're both error instances.\n* `compatibleConstructor(err, errorLike)` - Checks if an error's constructor is compatible with another `errorLike` object. If `err` has the same constructor as `errorLike` or if `err` is an instance of `errorLike`.\n* `compatibleMessage(err, errMatcher)` - Checks if an error message is compatible with an `errMatcher` RegExp or String (we check if the message contains the String).\n* `getConstructorName(errorLike)` - Retrieves the name of a constructor, an error's constructor or `errorLike` itself if it's not an error instance or constructor.\n* `getMessage(err)` - Retrieves the message of an error or `err` itself if it's a String. If `err` or `err.message` is undefined we return an empty String.\n\n```js\nvar checkError = require('check-error');\n```\n\n#### .compatibleInstance(err, errorLike)\n\n```js\nvar checkError = require('check-error');\n\nvar funcThatThrows = function() { throw new TypeError('I am a TypeError') };\nvar caughtErr;\n\ntry {\n funcThatThrows();\n} catch(e) {\n caughtErr = e;\n}\n\nvar sameInstance = caughtErr;\n\ncheckError.compatibleInstance(caughtErr, sameInstance); // true\ncheckError.compatibleInstance(caughtErr, new TypeError('Another error')); // false\n```\n\n#### .compatibleConstructor(err, errorLike)\n\n```js\nvar checkError = require('check-error');\n\nvar funcThatThrows = function() { throw new TypeError('I am a TypeError') };\nvar caughtErr;\n\ntry {\n funcThatThrows();\n} catch(e) {\n caughtErr = e;\n}\n\ncheckError.compatibleConstructor(caughtErr, Error); // true\ncheckError.compatibleConstructor(caughtErr, TypeError); // true\ncheckError.compatibleConstructor(caughtErr, RangeError); // false\n```\n\n#### .compatibleMessage(err, errMatcher)\n\n```js\nvar checkError = require('check-error');\n\nvar funcThatThrows = function() { throw new TypeError('I am a TypeError') };\nvar caughtErr;\n\ntry {\n funcThatThrows();\n} catch(e) {\n caughtErr = e;\n}\n\nvar sameInstance = caughtErr;\n\ncheckError.compatibleMessage(caughtErr, /TypeError$/); // true\ncheckError.compatibleMessage(caughtErr, 'I am a'); // true\ncheckError.compatibleMessage(caughtErr, /unicorn/); // false\ncheckError.compatibleMessage(caughtErr, 'I do not exist'); // false\n```\n\n#### .getConstructorName(errorLike)\n\n```js\nvar checkError = require('check-error');\n\nvar funcThatThrows = function() { throw new TypeError('I am a TypeError') };\nvar caughtErr;\n\ntry {\n funcThatThrows();\n} catch(e) {\n caughtErr = e;\n}\n\nvar sameInstance = caughtErr;\n\ncheckError.getConstructorName(caughtErr) // 'TypeError'\n```\n\n#### .getMessage(err)\n\n```js\nvar checkError = require('check-error');\n\nvar funcThatThrows = function() { throw new TypeError('I am a TypeError') };\nvar caughtErr;\n\ntry {\n funcThatThrows();\n} catch(e) {\n caughtErr = e;\n}\n\nvar sameInstance = caughtErr;\n\ncheckError.getMessage(caughtErr) // 'I am a TypeError'\n```"
}
![\"ChaiJS\"](\"http://chaijs.com/img/chai-logo.png\"/){kind=logo}
check-error\n \n