common-errors
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
Install
npm install common-errors
Class Directory
Common Error Classes
- AlreadyInUseError
- ArgumentError
- ArgumentNullError
- AuthenticationRequiredError
- ConnectionError
- DataError
- Error
- HttpStatusError
- InvalidOperationError
- IOError
- NotFoundError
- NotImplementedError
- NotPermittedError
- NotSupportedError
- OutOfMemoryError
- RangeError
- ReferenceError
- StackOverflowError
- SyntaxError
- TimeoutError
- TypeError
- URIError
- ValidationError
Utility Functions
Express Middleware Functions
Common Error Classes
AlreadyInUseError
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
// Example
throw new errors.AlreadyInUseError('user', 'username');ArgumentError
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.
// Example
throw new errors.ArgumentError('username', err);ArgumentNullError
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.
// Example
throw new errors.ArgumentNullError('username', err);AuthenticationRequiredError
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.
// Example
throw new errors.AuthenticationRequiredError("Please provide authentication.", err)ConnectionError
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.
// Example
throw new errors.ConnectionError('database connection no longer available', err);DataError
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.
// Example
throw new errors.data.DataError('Too many rows returned from database', err);MemcachedError
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.
// Example
throw new errors.data.MemcachedError('Expected value not found', err);MongoDBError
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.
// Example
throw new errors.data.MongoDBError('Retrieved value not in expected format', err);RedisError
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.
// Example
throw new errors.data.RedisError('expected value not found in redis', err);RollbackError
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.
// Example
throw new errors.data.RollbackError('database transaction was unexpectedly rolled back', err);SQLError
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.
// Example
throw new errors.data.SQLError('foreign key constraint violated', err);TransactionError
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.
// Example
throw new errors.data.TransactionError('transaction already complete', err);Error
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.
// Example
throw new errors.Error("Please provide authentication.", err)HttpStatusError
Represents a message and a HTTP status code.
new HttpStatusError(status_code[, message])
Arguments
status_code- any HTTP status code integermessage- any message
// Example
throw new errors.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
// Example
throw new errors.HttpStatusError(err, req);InvalidOperationError
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.
// Example
throw new errors.InvalidOperationError('divide by zero', err);IOError
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.
// Example
throw new errors.io.IOError("Could not open file", err)DirectoryNotFoundError
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.
// Example
throw new errors.io.DirectoryNotFoundError("/var/log", err)DriveNotFoundError
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.
// Example
throw new errors.io.DriveNotFoundError("c", err)EndOfStreamError
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.
// Example
throw new errors.io.EndOfStreamError("EOS while reading header", err)FileLoadError
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.
// Example
throw new errors.io.FileLoadError("./package.json", err)FileNotFoundError
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.
// Example
throw new errors.io.FileNotFoundError("./package.json", err)SocketError
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.
// Example
throw new errors.SocketError('socket no longer available', err);NotFoundError
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.
// Example
throw new errors.NotFoundError("User", err)NotImplementedError
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.
// Example
throw new errors.NotImplementedError("Method is not yet implemented.", err)NotPermittedError
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.
// Example
throw new errors.NotPermittedError("username cannot be changed once set.", err)NotSupportedError
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.
// Example
throw new errors.NotSupportedError('Zero values', err);OutOfMemoryError
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.
// Example
throw new errors.OutOfMemoryError('Maximum mem size exceeded.', err);RangeError
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.
// Example
throw new errors.RangeError("Value must be between " + MIN + " and " + MAX, err);ReferenceError
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.
// Example
throw new errors.ReferenceError("x is not defined", err);StackOverflowError
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.
// Example
throw new errors.StackOverflowError('Stack overflow detected.', err);SyntaxError
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.
// Example
throw new errors.SyntaxError("Unexpected token a", err);TimeoutError
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.
// Example
throw new errors.TimeoutError('100ms', err);TypeError
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.
// Example
throw new errors.TypeError("number is not a function", err);URIError
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.
// Example
throw new errors.URIError("URI malformed", err);ValidationError
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.
// Example
function validateUsername(username){
var errors = new errors.ValidationError();
if(username.length < 3) errors.addError(new errors.ValidationError("username must be at least two characters long", "VAL_MIN_USERNAME_LENGTH", "username"));
if(/-%$*&!/.test(username)) errors.addError(new errors.ValidationError("username may not contain special characters", "VAL_USERNAME_SPECIALCHARS", "username"));
return errors;
}Utility Functions
Log
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
// Example
mysql.query('SELECT * `FROM` users', function(err, results){
if(err) return errors.log(err, "Had trouble retrieving users.");
console.log(results);
});prependCurrentStack
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
// Example
mysql.query('SELECT * `FROM` users', function(err, results){
if(err) {
return errors.prependCurrentStack(err); // caller has better idea of source of err
}
console.log(results);
});generateClass
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.
// Example
var ArgumentNullError = helpers.generateClass("ArgumentNullError", {
extends: ArgumentError,
args: ['argumentName'],
generateMessage: function(){
return "Missing argument: " + this.argumentName;
}
});
throw new ArgumentNullError("username");Express Middleware Functions
Crash Protector
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.
// Example
var app = express();
app.use(express.static(__dirname + '/../public'));
app.use(express.bodyParser());
app.use(errors.middleware.crashProtector());
//insert new middleware here
app.get('/healthcheck', function (req, res, next){res.send('YESOK')});
app.use(app.router);
app.use(errors.middleware.errorHandler);
module.exports = app;Error Handler
Express middleware that translates common errors into HTTP status codes and messages.
// Example
var app = express();
app.use(express.static(__dirname + '/../public'));
app.use(express.bodyParser());
app.use(errors.middleware.crashProtector());
//insert new middleware here
app.get('/healthcheck', function (req, res, next){res.send('YESOK')});
app.use(app.router);
app.use(errors.middleware.errorHandler);
module.exports = app;Authors
This library was developed by David Fenster at Shutterstock
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License
MIT © 2013-2017 Shutterstock Images, LLC