Common error classes and utility functions
- Full suite of node.js Error classes like most other modern languages
- Append stack traces from other asynchronously generated Errors
- Generate your own custom Error classes in one line
- Map HTTP status codes to Errors for automatic handling in web services and applications
npm install common-errors
- AlreadyInUseError
- ArgumentError
- ArgumentNullError
- AuthenticationRequiredError
- ConnectionError
- DataError
- Error
- HttpStatusError
- InvalidOperationError
- IOError
- NotFoundError
- NotImplementedError
- NotPermittedError
- NotSupportedError
- OutOfMemoryError
- RangeError
- ReferenceError
- StackOverflowError
- SyntaxError
- TimeoutError
- TypeError
- URIError
- ValidationError
Applicable when a resource is already in use, for example unique key constraints like a username.
new AlreadyInUseError(entityName, arg1, [arg2, arg3, arg4, ...])
Arguments
entityName- the entity that owns the protected resourceargs- the fields or attributes that are already in use
// Examplethrownewerrors.AlreadyInUseError('user','username');Applicable when there's a generic problem with an argument received by a function call.
new ArgumentError(argumentName[, inner_error])
Arguments
argumentName- the name of the argument that has a probleminner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.ArgumentError('username',err);Applicable when an argument received by a function call is null/undefined or empty.
new ArgumentNullError(argumentName[, inner_error])
Arguments
argumentName- the name of the argument that is nullinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.ArgumentNullError('username',err);Applicable when an operation requires authentication
new AuthenticationRequiredError(message, [inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.AuthenticationRequiredError("Please provide authentication.",err)Applicable when an error occurs on a connection.
new ConnectionError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.ConnectionError('database connection no longer available',err);Applicable when an error occurs on or with an external data source.
new DataError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.data.DataError('Too many rows returned from database',err);Applicable when an error occurs while using memcached.
new MemcachedError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.data.MemcachedError('Expected value not found',err);Applicable when an error occurs while using MongoDB.
new MongoDBError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.data.MongoDBError('Retrieved value not in expected format',err);Applicable when an error occurs while using redis.
new RedisError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.data.RedisError('expected value not found in redis',err);Applicable when a transaction was unexpectedly rolled back.
new RollbackError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.data.RollbackError('database transaction was unexpectedly rolled back',err);Applicable when an error occurs while using a SQL database.
new SQLError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.data.SQLError('foreign key constraint violated',err);Applicable when an error unexpectedly interrupts a transaction.
new TransactionError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.data.TransactionError('transaction already complete',err);This is roughly the same as the native Error class. It additionally supports an inner_error attribute.
new Error(message, [inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.Error("Please provide authentication.",err)Represents a message and a HTTP status code.
new HttpStatusError(status_code[, message])
Arguments
status_code- any HTTP status code integermessage- any message
// Examplethrownewerrors.HttpStatusError(404,"Not Found");new HttpStatusError(err[, req])
Figure out a proper status code and message from a given error. The current mapping of error codes to HTTP status codes is as follows:
{"ValidationError": 400,"ArgumentError": 400,"AuthenticationRequiredError": 401,"NotPermittedError": 403,"ArgumentNullError": 404// , or 400 depending on what's wrong with the request"NotFoundError": 404,"NotSupportedError": 405,"AlreadyInUseError": 409,}To change the mappings, modify HttpStatusError.message_map and HttpStatusError.code_map
Arguments
err- any instanceof Errorreq- the request object
// Examplethrownewerrors.HttpStatusError(err,req);Applicable when an invalid operation occurs.
new InvalidOperationError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.InvalidOperationError('divide by zero',err);Base class for Errors while accessing information using streams, files and directories.
new IOError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.io.IOError("Could not open file",err)Applicable when part of a file or directory cannot be found.
new DirectoryNotFoundError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.io.DirectoryNotFoundError("/var/log",err)Applicable when trying to access a drive or share that is not available.
new DriveNotFoundError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.io.DriveNotFoundError("c",err)Applicable when reading is attempted past the end of a stream.
new EndOfStreamError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.io.EndOfStreamError("EOS while reading header",err)Applicable when a file is found and read but cannot be loaded.
new FileLoadError(message[, inner_error])
Arguments
file_name- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.io.FileLoadError("./package.json",err)Applicable when an attempt to access a file that does not exist on disk fails.
new FileNotFoundError(message[, inner_error])
Arguments
file_name- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.io.FileNotFoundError("./package.json",err)Applicable when an error occurs on a socket.
new SocketError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.SocketError('socket no longer available',err);Applicable when an attempt to retrieve data yielded no result.
new NotFoundError(entity_name[, inner_error])
Arguments
entity_name- a description for what was not foundinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.NotFoundError("User",err)Applicable when a requested method or operation is not implemented.
new NotImplementedError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.NotImplementedError("Method is not yet implemented.",err)Applicable when an operation is not permitted
new NotPermittedError(message[, inner_error])
Arguments
message- any messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.NotPermittedError("username cannot be changed once set.",err)Applicable when a certain condition is not supported by your application.
new NotSupportedError(message[, inner_error])
Arguments
message- a messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.NotSupportedError('Zero values',err);Applicable when there is not enough memory to continue the execution of a program.
new OutOfMemoryError(message[, inner_error])
Arguments
message- a messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.OutOfMemoryError('Maximum mem size exceeded.',err);Represents an error that occurs when a numeric variable or parameter is outside of its valid range. This is roughly the same as the native RangeError class. It additionally supports an inner_error attribute.
new RangeError(message[, inner_error])
Arguments
message- a messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.RangeError("Value must be between "+MIN+" and "+MAX,err);Represents an error when a non-existent variable is referenced. This is roughly the same as the native ReferenceError class. It additionally supports an inner_error attribute.
new ReferenceError(message[, inner_error])
Arguments
message- a messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.ReferenceError("x is not defined",err);Applicable when the execution stack overflows because it contains too many nested method calls.
new StackOverflowError(message[, inner_error])
Arguments
message- a messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.StackOverflowError('Stack overflow detected.',err);Represents an error when trying to interpret syntactically invalid code. This is roughly the same as the native SyntaxError class. It additionally supports an inner_error attribute.
new SyntaxError(message[, inner_error])
Arguments
message- a messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.SyntaxError("Unexpected token a",err);Applicable when an operation takes longer than the alloted amount.
new TimeoutError(time[, inner_error])
Arguments
time- a time durationinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.TimeoutError('100ms',err);Represents an error when a value is not of the expected type. This is roughly the same as the native TypeError class. It additionally supports an inner_error attribute.
new TypeError(message[, inner_error])
Arguments
message- a messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.TypeError("number is not a function",err);Represents an error when a value is not of the expected type. This is roughly the same as the native URIError class. It additionally supports an inner_error attribute.
new URIError(message[, inner_error])
Arguments
message- a messageinner_error- the Error instance that caused the current error. Stack trace will be appended.
// Examplethrownewerrors.URIError("URI malformed",err);Useful for denoting a problem with a user-defined value. Generally, you won't throw this error. It serializes to JSON, and it can also function as an envelope for multiple errors.
new ValidationError(message, [code], [field])
Arguments
message- any messagecode- an optional error codefield- an optional description of the data
Methods
addError(error)- add an error object to theerrorsarray, and returnthis.addErrors(errors)- append an array of error objects to theerrorsarray, and returnthis.
// ExamplefunctionvalidateUsername(username){varerrors=newerrors.ValidationError();if(username.length<3)errors.addError(newerrors.ValidationError("username must be at least two characters long","VAL_MIN_USERNAME_LENGTH","username"));if(/-%$*&!/.test(username))errors.addError(newerrors.ValidationError("username may not contain special characters","VAL_USERNAME_SPECIALCHARS","username"));returnerrors;}Modifies an error's stack to include the current stack and logs it to stderr. Useful for logging errors received by a callback.
log(err[, message])
Arguments
err- any error or error message received from a callbackmessage- any message you'd like to prepend
// Examplemysql.query('SELECT * `FROM` users',function(err,results){if(err)returnerrors.log(err,"Had trouble retrieving users.");console.log(results);});Modifies an error's stack to include the current stack without logging it. Useful for logging errors received by a callback.
prependCurrentStack(err)
Arguments
err- any error or error message received from a callback
// Examplemysql.query('SELECT * `FROM` users',function(err,results){if(err){returnerrors.prependCurrentStack(err);// caller has better idea of source of err}console.log(results);});Simple interface for generating a new Error class type.
helpers.generateClass(name[, options])
Arguments
name- The full name of the new Error classoptionsextends- The base class for the new Error class. Default isError.globalize- Boolean (defaulttrue) to store the Error in global space so that the Error is equivalent to others included from other versions of the module.args- Array of names of values to accept and store from the class constructor. Default is['message', 'inner_error'].generateMessage- A function for defining a custom error message.
// ExamplevarArgumentNullError=helpers.generateClass("ArgumentNullError",{extends: ArgumentError,args: ['argumentName'],generateMessage: function(){return"Missing argument: "+this.argumentName;}});thrownewArgumentNullError("username");Express middleware for preventing the web server from crashing when an error is thrown from an asynchronous context.
Any error that would have caused a crash is logged to stderr.
// Examplevarapp=express();app.use(express.static(__dirname+'/../public'));app.use(express.bodyParser());app.use(errors.middleware.crashProtector());//insert new middleware hereapp.get('/healthcheck',function(req,res,next){res.send('YESOK')});app.use(app.router);app.use(errors.middleware.errorHandler);module.exports=app;Express middleware that translates common errors into HTTP status codes and messages.
// Examplevarapp=express();app.use(express.static(__dirname+'/../public'));app.use(express.bodyParser());app.use(errors.middleware.crashProtector());//insert new middleware hereapp.get('/healthcheck',function(req,res,next){res.send('YESOK')});app.use(app.router);app.use(errors.middleware.errorHandler);module.exports=app;This library was developed by David Fenster at Shutterstock
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