Errors : object

Custom Node and Browser Error Classes

npm install node-error-classes

Easy to read isomorphic, custom and extensible error classes for node.js and the browser that extend the native error classes.

This will work in the browser too with webpack, browserify, or any other common.js module loader!

Sometimes, just throwing an error isn't that helpful. Sometimes, handling an error elegantly preventing a crash just isn't quite good enough. During team development there are times when you want to throw explicit errors to both help developers understand whats going on, as well as enforce some strict rules. That is what this module is for.

Kind: global namespace
Example

'use strict';

Errors=require('node-error-classes');

• Errors : object
  • .Immutable ⇐ Error
    • new Immutable()
    • .setMessage(varaibleName, scope) ⇒ String
  • .InvalidMethod ⇐ Error
    • new InvalidMethod()
    • .setMessage(methodName, method, [scope]) ⇒ String
  • .InvalidParameter ⇐ Error
    • new InvalidParameter()
    • .setMessage(parameterName, expected, got, [scope]) ⇒ String
  • .RequiredParameter ⇐ Error
    • new RequiredParameter()
    • .setMessage(parameterName, [scope]) ⇒ String
  • .SocketUnavailable ⇐ Error
    • new SocketUnavailable()
    • .setMessage(socketPath, [scope]) ⇒ String
  • .Type ⇐ TypeError
    • new Type()
    • .setMessage(parameterName, type, value, [scope]) ⇒ String
  • .UndefinedValue ⇐ Error
    • new UndefinedValue()
    • .setMessage(variableName, variable, [scope]) ⇒ String

Errors.Immutable ⇐ Error

Kind: static class of Errors
Extends: Error

• .Immutable ⇐ Error
  • new Immutable()
  • .setMessage(varaibleName, scope) ⇒ String

new Immutable()

Error for Immutable variables

Immutable.setMessage(varaibleName, scope) ⇒ String

Kind: static method of Immutable
Returns: String - compiled error message

| Param | Type | Description | | --- | --- | --- | | varaibleName | String | name of immutable variable | | scope | Any | Scope of varaible |

Example

const Errors = require('node-error-classes');
    class User{
        constructor(name,age){
            Object.defineProperties(
                this,
                {
                    age:{
                        enumerable:true,
                        writable:true,
                        value:age
                    },
                    name:{
                        enumerable:true,
                        get:getName,
                        set:setName
                    }
                }
            );

            let userName=null;

            function getName(){
                return userName;
            }

            function setName(value){
                if(userName){
                    const err=new Errors.Immutable;
                    err.setMessage(
                        'name',
                        this
                    );

                    throw err;
                }
                userName=value;
                return userName;
            }

            if(name){
                this.name=name;
            }
        }
    }

    const bob=new User('bob',42);

    bob.name='bob';

Example

     git/node-error-classes/example/immutable.js:40
                   throw err;
                   ^

    Immutable: 'name' is Immutable and may not be modified.
            User { age: 42, name: [Getter/Setter] }
        at Immutable (/home/bmiller/git/node-error-classes/lib/Immutable.js:10:1)
        at User.setName [as name] (/home/bmiller/git/node-error-classes/example/immutable.js:34:26)

Errors.InvalidMethod ⇐ Error

Kind: static class of Errors
Extends: Error

• .InvalidMethod ⇐ Error
  • new InvalidMethod()
  • .setMessage(methodName, method, [scope]) ⇒ String

new InvalidMethod()

Error for methods which are either undefined or not methods (functions)

InvalidMethod.setMessage(methodName, method, [scope]) ⇒ String

Kind: static method of InvalidMethod
Returns: String - compiled error message

| Param | Type | Description | | --- | --- | --- | | methodName | String | method name | | method | Any | expected method | | [scope] | Any | scope in which the invalid method is expected |

Example

const Errors = require('node-error-classes');

         class User{
            constructor(name,age){
                this.name=name;
                this.age=age;
            }
         }

        const bob=new User('bob',42);

        if(!bob.getInfo || typeof bob.getInfo !== 'function'){
            const err=new Errors.InvalidMethod;
            err.setMessage('getInfo',bob.getInfo,bob);
        }

Example

git/node-error-classes/example/invalidMethod.js:23
       throw err;
       ^

    UndefinedMethod: Expects 'getInfo' to be Function but got undefined
                Scope : User { name: 'bob', age: 42 }
        at InvalidMethod (/home/bmiller/git/node-error-classes/lib/InvalidMethod.js:10:1)
        at Object.<anonymous> (/home/bmiller/git/node-error-classes/example/invalidMethod.js:15:14)

Errors.InvalidParameter ⇐ Error

Kind: static class of Errors
Extends: Error

• .InvalidParameter ⇐ Error
  • new InvalidParameter()
  • .setMessage(parameterName, expected, got, [scope]) ⇒ String

new InvalidParameter()

Error for invalid parameters

InvalidParameter.setMessage(parameterName, expected, got, [scope]) ⇒ String

Kind: static method of InvalidParameter
Returns: String - compiled error message

| Param | Type | Description | | --- | --- | --- | | parameterName | Any | name of parameter | | expected | Any | what it expected | | got | Any | what it got | | [scope] | Any | optional value where the parameter came from like an object or array |

Example

let test={a:1,b:0};

if(test.b<1){
    err=new Errors.InvalidParameter;
    err.setMessage(
        'b',
        'a value greater than 0',
        test.b,
        test
    );
    throw err;
}

Example

git/node-error-classes/example/invalidParam.js:19
        throw err;
        ^

        InvalidParameter: 'b' Expects 'a value greater than 0' but got 0

        at InvalidParameter (/home/bmiller/git/node-error-classes/lib/InvalidParameter.js:11:1)
        at multiplyNumbers (/home/bmiller/git/node-error-classes/example/invalidParam.js:13:13)

Errors.RequiredParameter ⇐ Error

Kind: static class of Errors
Extends: Error

• .RequiredParameter ⇐ Error
  • new RequiredParameter()
  • .setMessage(parameterName, [scope]) ⇒ String

new RequiredParameter()

error for required params that are not set or passed

RequiredParameter.setMessage(parameterName, [scope]) ⇒ String

Kind: static method of RequiredParameter
Returns: String - compiled error message

| Param | Type | Description | | --- | --- | --- | | parameterName | Any | name of parameter | | [scope] | Any | optional value where the parameter came from like an object or array |

Example

let test={a:1,b:0};

if(!test.c){
    err=new Errors.RequiredParameter;
    err.setMessage(
        'c',
        test
    );
    throw err;
}

Example

git/node-error-classes/example/requiredParam.js:17
        throw err;
        ^

        RequiredParameter: Expects 'numberOne' to be defined

        at RequiredParameter (/home/bmiller/git/node-error-classes/lib/RequiredParameter.js:12:1)
        at multiplyNumbers (/home/bmiller/git/node-error-classes/example/requiredParam.js:13:13)

Errors.SocketUnavailable ⇐ Error

Kind: static class of Errors
Extends: Error

• .SocketUnavailable ⇐ Error
  • new SocketUnavailable()
  • .setMessage(socketPath, [scope]) ⇒ String

new SocketUnavailable()

Error for when an expected socket is not available

SocketUnavailable.setMessage(socketPath, [scope]) ⇒ String

Kind: static method of SocketUnavailable
Returns: String - compiled error message

| Param | Type | Description | | --- | --- | --- | | socketPath | Any | name of parameter | | [scope] | Any | optional value with information on the socket or constructor |

Example

const ipc=require('node-ipc');
        const Errors=require('node-error-classes');
        ipc.config.id   = 'hello';
        ipc.config.maxRetries = 3;
        ipc.config.silent=true;

        ipc.connectTo(
            'world',
            function(){
                ipc.of.world.on(
                    'destroy',
                    function(data){
                        const err=new Errors.SocketUnavailable;
                        err.setMessage(
                            ipc.of.world.path,
                            ipc.of.world
                        );
                        throw err;
                    }
                );
            }
        );

Example

        git/node-error-classes/example/socketUnavailable.js:19
                throw err;
                ^

        SocketUnavailable: Socket of '/tmp/app.world' Unavailable

        at SocketUnavailable (/home/bmiller/git/node-error-classes/lib/SocketUnavailable.js:11:1)
        at Object.<anonymous> (/home/bmiller/git/node-error-classes/example/socketUnavailable.js:14:27)
        at Object.pub (/home/bmiller/git/node-error-classes/node_modules/node-ipc/node_modules/event-pubsub/event-pubsub.js:69:19)
        at Object.trigger (/home/bmiller/git/node-error-classes/node_modules/node-ipc/node_modules/event-pubsub/event-pubsub.js:111:21)
        at Socket.connectionClosed (/home/bmiller/git/node-error-classes/node_modules/node-ipc/dao/client.js:157:24)
        at emitOne (events.js:77:13)
        at Socket.emit (events.js:169:7)
        at Pipe._onclose (net.js:469:12)

Errors.Type ⇐ TypeError

Kind: static class of Errors
Extends: TypeError

• .Type ⇐ TypeError
  • new Type()
  • .setMessage(parameterName, type, value, [scope]) ⇒ String

new Type()

Used for normalizing the message of a type error

Type.setMessage(parameterName, type, value, [scope]) ⇒ String

Kind: static method of Type
Returns: String - compiled error message

| Param | Type | Description | | --- | --- | --- | | parameterName | Any | name of parameter | | type | String | Type String | | value | Any | value that caused error | | [scope] | Any | optional value where the parameter came from like an object or array |

Example

let test={a:1,b:0};

if(typeof test.b!=='object'){
    err=new Errors.Type;
    err.setMessage(
        'b',
        'Object',
        test.b,
        test
    );
    throw err;
}

Example

git/node-error-classes/example/typeError.js:19
        throw err;
        ^

        TypeError: 'numberOne' Expects String but got number : 6

        at Type (/home/bmiller/git/node-error-classes/lib/Type.js:12:1)
        at multiplyNumbers (/home/bmiller/git/node-error-classes/example/typeError.js:13:13)

Errors.UndefinedValue ⇐ Error

Kind: static class of Errors
Extends: Error

• .UndefinedValue ⇐ Error
  • new UndefinedValue()
  • .setMessage(variableName, variable, [scope]) ⇒ String

new UndefinedValue()

Error for undefined values

UndefinedValue.setMessage(variableName, variable, [scope]) ⇒ String

Kind: static method of UndefinedValue
Returns: String - compiled error message

| Param | Type | Description | | --- | --- | --- | | variableName | String | varible name | | variable | Any | varible | | [scope] | Any | scope in which the variable should exist |

Example

const Errors = require('node-error-classes');

    const user={
       name:'bob'
    }

    if(!user.age){
      const err = new Errors.UndefinedValue;
      err.setMessage(
          'age',
          user.age,
          user
      );
      throw err;
    }

Example

    git/node-error-classes/example/undefinedValue.js:14
       throw err;
       ^

    Undefined: 'string'