simple-ioc

Simple-ioc is a module for simple inversion of control for node.js. Main features are:

• Easy dependency injection without special syntax - in most cases modules can be used without simple-ioc.
• Easy exchangeability of components - settings can determine which components that should be used in different environments.
• Automatic asynchronous resolving - components are only resolved when all dependencies are resolved

Installation

Simple-ioc is installed from npm.

npm install simple-ioc

Basic usage and simple example

The following is a simple example of how to use simple-ioc

Example of usage

// ./lib/store.js
module.exports = function( databaseAdapter, callback ) {
	databaseAdapter.connect( function( err, connection ) {
		if( err ) {
        	console.log( err );
        	process.exit( 1 ); // Application cannot start!
        }
		else {
        	var pub = {};
			pub.getData = function( callback ) {
				connection.query( callback );
			};
            callback( pub );
		}
	} );
};

// ./lib/module1.js
module.exports = function( pub, store ) {
	pub.printData = function() {
    	store.getData( function( err, data ) {
    	} );
    };
};

// ./index.js
module.exports = require( 'simple-ioc' )
	.getContainer()
    .registerResolved( 'databaseAdapter', require( 'some-database-adapter' )
    .autoRegisterPath( './lib' )
    .inject( function( module1 ) {
    	module1.printdata();
    } );

### Reserved dependencies Simple-ioc has a number of reserved dependencies that cannot be registered in containers, these are:

• pub
• parentName
• callback
• setup

Additionally every container has the following pre-registered components, which makes them virtually reserved as well:

• ioc
• container
• errRerouter

#### pub A module can return its instance in two ways, either by creating the instance itself and returing it (or by using it as the argument asynchronously to the callback, see section [`callback`](#iocCallback) for more information) or by depending on `pub` and attaching properties to this object.

The use of pub is optional. It might be handy but it complicates using the module without the ioc, so use it only when you feel comfortable with simple-ioc.

Example:

module.exports = function() {
	var pub = {};
    pub.func = function() {};
	return pub;
};

is equivalent to:

module.exports = function( pub ) {
	pub.func = function() {};
};

If using pub the module is more complex to resolve without the ioc. It can still be done by doing something like this:

var resolved = {};
myModule( resolved );

#### parentName Normally all components registered in a container have a singleton lifestyle, but for some components this is not desired. To make a component transient simply let it depend on `parentName`. This way the component will be resolved everytime it is injected.

Example:

var container = require( 'simple-ioc' )
	.getContainer()
    .registerInjectable( {
    	transientModule: function( parentName ) {
        	return function() {
            	console.log( parentName );
            };
        },
        singletonModule1: function( transientModule ) {
        	return transientModule;
        },
        singletonModule2: function( transientModule ) {
        	return transientModule;
        }
    } )
    .inject( function( singletonModule1, singletonModule2 ) {
    	singletonModule1(); // Will output "singletonModule1"
    	singletonModule2(); // Will output "singletonModule2"
    } );

#### callback Some components might need asynchronous calls before they can be used. By depending on `callback` the container waits for the callback to be invoked before it considers the component ready. If [`pub`](#pub) is not used the resolved instance should be used as the first argument to `callback`.

Example:

var container = require( 'simple-ioc' )
	.getContainer()
    .registerInjectable( {
    	asyncModule: function( callback ) {
        	var pub = {};
			someAsyncSetup( function( err, something ) {
            	pub.func = function() {
                	something();
                };
                callback( pub );
            } );
		}
    } )
    .inject( function( asyncModule ) {
    	asyncModule.fun(); // asyncModule is ready to be used
    } );

#### setup In future versions of simple-ioc it will be possible to automatically create test-stubs for component. For components that needs to be setup with external dependencies, it might be necessary to resolve components without a "real" setup, so simple-ioc can inspect the component. To prepeare for this it is possible to use `setup`. In normal use setup can be invoked with a function that will be called when the component is resolved.

Note that this this is not implemented yet, but might be a good idea to use.

Example:

var container = require( 'simple-ioc' )
	.getContainer()
    .registerInjectable( {
    	module1: function( setup, callback ) {
        	var pub = {},
            	something;
            pub.func = function() {
                something();
            };
            setup( function() {
				someAsyncSetup( function( err, _something ) {
                	something = _something;
    	            callback( pub );
        	    } );
			} );
		}
    } );

Documentation

ioc

• getContainer()
• setSettings( settings1, settings2, settings3, ... )
• getSettings()
• useLogWriter( resolvedWriter )

container

• registerResolved( name, instance )
• registerInjectable( name, fn )
• mock( name, properties )
• registerGlobalWrappersFromSettings( settingsKey )
• autoRegisterPath( relativePath, [omitFileIocComments], [omitFileLengthLogging] )
• resolve( name, callback )
• registerIocSettings( name )
• registerIocLog( name )
• resolveAllAndInject( fn )
• injectAfterResolveAll( fn )
• inject( fn, [callback] )
• registerResolvedIfSetting( settingKey, name, instance )
• registerInjectableIfSetting( settingKey, name, fn )
• autoRegisterPathInSetting( settingKey )
• removeRegistered( name )
• export( name )

log

• fatal( message, [ data ] )
• error( message, [ data ] )
• warning( message, [ data ] )
• info( message, [ data ] )
• debug( message, [ data ] )
• trace( message, [ data ] )
• getEntries( [componentName] )
• reset()

errRerouter

• ( callback, fn )

## ioc

The main function of the ioc is to create containers, but it also has a built-in log and settings.

---

### getContainer() Creates a new container.

Arguments

None.

Returns

A new container.

Remarks

The ioc, the container itself and errRerouter is registered automaticaly to the new container.

Example

var container = require( 'simple-ioc' ).getContainer()

---

### setSettings( settings1, settings2, settings3, ... ) Sets the settings the ioc will read, initially the sttings will have a log-property, see section [log](#log) for more information about the built-in logger.

Arguments

Variable amount of objects with settings, the settings will be merged with the existing settings.

Returns

The ioc.

Remarks

The ioc has 5 built-in output-writers, these are

• consoleJson - More or less console.log( JSON.stringify( logObject ) )
• bunyanJson - Same idea of consoleJson, but you can use bunyan command to read pretty printed errors as an human.
• consoleReadable - Logs in a readable format, with some coloring of level
• devNull - writes nothing
• memoryJson - writes to memory, which is searchable afterwards. This should never be used in production, only in tests.

The default settings are:

{
	log: {
		level: 0,
		includeEnvironmentVariables: { env: 'NODE_ENV' },
		output: 'devNull'
	}
}

Example

require( 'simple-ioc' ).setSettings(
	{
		log: {
			level: 3
		}
    },
	{
		log: {
			output: 'consoleReadable'
		}
	}
);
/*
will result in the following settings
{
	log: {
		level: 3,
		includeEnvironmentVariables: { env: 'NODE_ENV' },
		output: 'consoleReadable'
	}
}
*/

Bunyan Example

node-bunyan is a medium-complex logging solution, integration in simple-ioc is really minimal, and completely optional. To use the bunyan writer you have to add bunyan to your project dependencies.

require( 'simple-ioc' ).setSettings(
    {
        log: {
            output: 'bunyanJson'
        }
    }
);

Then you can pipe the output of your program to bunyan command for pretty-print.

---

### getSettings() Gets the settings the ioc uses. See [registerIocSettings](#registerIocSettings) how to register settings in a container for injection.

Arguments

None.

Returns

The registered settings

Remarks

Normally this function is not used, instead settings are injected, but might be useful for debugging.

Example

require( 'simple-ioc' ).setSettings( {
	key: 'value'
} ).getSettings();
/* Will return
{
	log: {
		level: 0,
		includeEnvironmentVariables: { env: 'NODE_ENV' },
		output: 'devNull'
	},
    key: 'value'
}
*/

---

### useLogWriter( resolvedWriter ) The built-in logger (see [log](#log) for information) can also use a external output writer, it must implement the following functions:

• output( logObject ) - called on every log that is on a level that should be logged.
• getEntries( component ) - can be implemented, but should not be used in production.
• reset() - to reset the log entries.

Arguments

• resolvedWriter an object that implements at least output( logObject )

Returns

The ioc.

Remarks

None.

Example

require( 'simple-ioc' ).useLogWriter( {
	output: function( logObject ) {
		console.log( logObject.level );
	}
} );
// Will only ouptut the level of the log (numeric) to the console.

---

container

Containers are the central part of the ioc, it stores and resolves components.

Note: All functions on the container returns the container itself.

### registerResolved( name, instance ) Registers a already resolved component to the container, e.g. external componens like "express".

Arguments

• name - the identifying name of the component
• instance - the resolved instance

OR

• name - An object with key/value pairs reprecenting names/instances

Returns

The container

Remarks

Packages that have a simple name (without special characters, such as "-") and are possible to require within the current scope, does not need to be registered. For example, a module can have a dependency to "http" without it being registered. If a dependency exists to a component that is not registered, the container will try to require the name of the dependency and register it as a singleton if successful.

Example

var container = require( 'simple-ioc' ).getContainer()
	.registerResolved( async: require( 'async' ) ) // Registers async
	.registerResolved( { // Registers express and request
		express: require( 'express' ),
		request: require( 'request' )
	} )
    .inject( function( express, http, request, async ) {
    	// Will succeed since the container will register http automatically.
    } );

---

### registerInjectable( name, fn ) Registers an injectable component in the container, this method should normally be used when registering internal libraries which can use their own containers.

Arguments

• name - the identifying name of the component
• fn - the injectable function

OR

• name - An object with key/value pairs reprecenting names/instances

Returns

The container.

Remarks

Injectable functions has some reserved parameternames used by the ioc, these cannot be registered or used as normal dependencies. See Reserved dependencies for more information.

Example

var container = require( 'simple-ioc' ).getContainer()
	.registerInjectable( 'myComponent', function( pub, callback ) {
		pub.func1 = function( params ) {
			return whatEver;
		};
		doSomething( function() {
			callback();
		} )
	} ) // Registers a singleton component that has an async setup and a function func1 as myComponent
	.registerInjectable( {
		anotherComponent: function( setup, pub, callback ) {
			setup( function() {
				someSetup( function() {
					pub.xxx = function() {
						return amazingStuff;
					};
					callback();
				} );
			} );
			// Registers a singleton component that has a setup that also is async. The result is a
			// component registered as anotherComponent with a function xxx.
		},
		yetAnother: function( parentName ) {
			return {
				func3: function() {
					return parentName;
				}
			};
			// Registeres a transient component as yetAnother with a function func3. Everytime yetAnother
			// is injected the registered function will be called, creating a new enclosed scope.
		}
	} );

---

### mock( name, properties ) Simple-ioc has a built-in mocking function, making it easier to mock modules with sync and async functions. Mock is not supposed to be used in production code, but rather in tests.

Arguments

• name name of the component to mock
• properties the properties to mock with functions, setting the default value of the mocked function

or

• name an object with key/value pairs reprecenting names/properties

Returns

The container

Remarks

Mocking of modules by using "mock" might not be totaly straight forward and cannot be used in every mocking situation. See the example how a possible way to use it and how to achieve the same result without using mock. The values of mocked functions can be changed by setting the properties later.

Mock checks when a function is invoked, if last parameter is a function it will treat is as an async function.

Example

require( 'simple-ioc' )
	.getContainer()
    .mock( {
    	module1: {
        	sync: 'syncVal',
            async: 'asyncVal'
        }
    } )
    .registerResolved( { // module2 is mocked without using mock
    	module2: {
        	sync: function() {
            	return 'syncVal';
            },
            async: function( param1, callback ) {
            	callback( undefined, 'asyncVal' ); 
            }
        }
    } )
    .inject( function( assert, module1, module2 ) {
		// Sync
		assert.equal( module1.sync(), 'syncVal' );
    	assert.equal( module2.sync(), 'syncVal' );
        // Async
    	module1.async( 'test', function( err, value ) {
        	assert.ok( !err );
			assert.equal( value, 'asyncVal' );
		} );
    	module2.async( 'test', function( err, value ) {
        	assert.ok( !err );
			assert.equal( value, 'asyncVal' );
		} );
        // Changing sync
        module1.sync = 'newSyncVal'; // Changing what sync will return when invoked
        module2.sync = function() { // ... same without mock
        	return 'newSyncVal';
        };
    	assert.equal( module1.sync(), 'newSyncVal' );
    	assert.equal( module2.sync(), 'newSyncVal' );
        // Changing async
        module1.async = 'newAsyncVal'; // Changing what async will callback when invoked
        module2.async = function( param1, callback ) { // ... same without mock
        	callback( undefined, 'newAsyncVal' ); 
		};
    	module1.async( 'test', function( err, value ) {
        	assert.ok( !err );
			assert.equal( value, 'newAsyncVal' );
		} );
    	module2.async( 'test', function( err, value ) {
        	assert.ok( !err );
			assert.equal( value, 'newAsyncVal' );
		} );
        // Change so async callbacks an error
		module1.async.err = 'myError'; // Change async so it callbacks with an error
        module2.async = function( param1, callback ) { // ... same without mock
        	callback( 'myError' ); 
		};
    	module1.async( 'test', function( err, value ) {
        	assert.equal( err, 'myError' );
		} );
    	module2.async( 'test', function( err, value ) {
        	assert.equal( err, 'myError' );
		} );
    } );

---

### registerGlobalWrappersFromSettings( settingsKey ) Simple-ioc offers a method of wrapping methods in components of registered components. This can be useful if interception of calls are needed for tracking or debugging.

Arguments

• settingsKey the key in settings that specifies which components should be wrapped

Returns

The container.

Remarks

Wrappers can implement functions async and or sync, see example of usage. Wrapping is global and affects all containers in the ioc.

Example

require( 'simple-ioc' )
    .setSettings( {
        wrapping: {
            request: 'requestWrapper',
            module1: 'syncWrapper'
        }
    } )
    .registerResolved( {
        request: require( 'request' )
    } )
    .registerInjectable( {
        module1: function( pub ) {
            pub.func = function( param1, param2 ) {
                return param1 + param2;
            };
        },
        requestWrapper: function( assert, pub ) {
            pub.async = function( context, arguments, callback ) {
                assert.equal( context.async, true );
                var wrappedComponent = context.parentName; // e.g. request
                var wrappedFunction = context.wrappedFunction; // e.g. get
                var timeOfExecution = context.ts;
                var executionTime = context.executionTime;
                var result = context.result;
                var argumentsToFunction = arguments; // e.g. [ 'www.google.com' ]
                // Do something with this information, e.g. logging
                callback( function( err, result ) { // Will be invoked when on async callback
                    // Do some more logging... e.g. time = Date.now() - timeOfExecution;
                } );
            }
        },
        syncWrapper: function( assert, pub ) {
            pub.sync = function( context, arguments, result ) {
                assert.equal( context.sync, true );
                var wrappedComponent = context.parentName; // e.g. module1
                var wrappedFunction = context.wrappedFunction; // e.g. func
                var timeOfExecution = context.ts;
                var argumentsToFunction = arguments; // e.g. [ 1, 2 ]
                var resultOfInvokation = result; // e.g. 3
                // Do something with this information, e.g. logging
            };
        }
    } )
    .registerGlobalWrappersFromSettings( 'wrapping' )
    .inject( function( request, module1 ) {
        request.get( 'www.google.com', function( err, res, body ) {
            // wrapper has been called before request and when responce is received.
        } );
        var result = module1.func( 1, 2 ); // wrapper has been called
    } );

---

### autoRegisterPath( relativePath, [omitFileIocComments], [omitFileLengthLogging] ) Register all files in the given path, using function name or, if not existing, the file name as name of component.

Arguments

• relativePath relative path or absolut path that th container will recursively look in.
• omitFileIocComments (optinal) default false, if true, the container will not look for ioc specific comments.
• omitFileLengthLogging (optional) default false, if true, no warnings for long files.

Returns

The container.

Remarks

Files that contains the followin comments will be handeled different by autoRegisterPath:

• /* ioc:ignore */ - file will be ignored.
• /* ioc:noresolve */ - file will be registered as resolved

If omitFileLengthLogging is not set, the ioc will info log if files exceed 100 lines and warning log if files exceed 200 lines.

Normally the ioc uses the name of the file as name of the component, but if the function is not anonymous, the name of the function is used. In case the name of the component is hyphenated (some-component.js), it will be camelCased when injected (someComponent).

Example

// ./lib/module1.js
module.exports = function( pub ) {
	pub.name = 'mod1';
};

// ./lib/module2.js
module.exports = function( pub, module1 ) {
	pub.name = [ module1.name, 'mod2' ].join( '.' );
};

// ./lib/module3ButWithAnotherName.js
module.exports = function module3( pub, module2 ) {
	pub.name = [ module2.name, 'mod3' ].join( '.' );
};

// ./index.js
module.exports = require( 'simple-ioc' )
	.getContainer()
    .autoRegisterPath( './lib' )
    .inject( function( module3 ) {
    	console.log( module3.name ); // Will print out "mod1.mod2.mod3"
    } );

---

### resolve( name, callback )

Arguments

• name name of the component to resolve
• callback( err, instance ) function to be called with the result of the resolve.

Returns

The container.

Remarks

Resolve can safely be used anytime, since it callbacks an error if the component is unresolvable.

Example

var assert = require( 'assert' ); 
module.exports = require( 'simple-ioc' )
	.getContainer()
    .registerInjectable( {
    	test: function( pub ) {}
    } )
    .resolve( 'test', function( err, instance ) {
		assert.ok( !err );
        assert.ok( !!pub );
	} )
    .resolve( 'notRegistered', function( err, instance ) {
		assert.ok( err );
        assert.ok( !pub );
	} )

---

### registerIocSettings( [ name ] ) Registers the ioc settings to the container with the specified name.

Arguments

• name the name settings should be registerd as, defaults to "settings"

Returns

The container.

Remarks

None.

Example

var assert = require( 'assert' ); 
module.exports = require( 'simple-ioc' )
	.setSettings( {
    	key: 'value'
    } )
	.getContainer()
    .registerIocSettings()
    .inject( function( settings ) {
		assert.equal( settings.key, 'value' );
	} );

---

### registerIocLog( [ name ] ) Registers the build-in ioc logger to the container with the specified name.

Arguments

• name the name settings should be registerd as, defaults to "log"

Returns

The container.

Remarks

None.

Example

var assert = require( 'assert' ); 
module.exports = require( 'simple-ioc' )
	.getContainer()
    .registerIocLog( 'log' )
    .inject( function( log ) {
		assert.ok( !!log.info );
	} );

---

### resolveAllAndInject( fn ) Resolves all components that are unresolved and registered with singleton lifestyle. Finally the `fn` function is injected.

Arguments

• fn function to inject after all registered injectable singleton components are resolved.

Returns

The container.

Remarks

ResolveAllAndInject will log information about components that does not have any components that are depending on them.

Example

var assert = require( 'assert' ); 
module.exports = require( 'simple-ioc' )
	.getContainer()
    .registerInjectable( {
    	module1: function( pub ) {
        	console.log( 'module1' );
            pub.value = 'val1';
        },
        module2: function( module1, callback ) {
        	console.log( 'module2' );
            callback( {
            	value: [ module1.value, 'val2' ].join( '.' );
            } );
        }
    } )
    .resolveAllAndInject( function() {
    	console.log( 'injected' );
    } );
    // Will have the following output:
    // module1
    // module2
    // injected

---

### inject( fn, [ callback ] ) Gives the possibility to inject anonymous functions

Arguments

• fn function to inject.
• callback optional, called after the functions is injected.

Returns

The container

Remarks

None.

Example

var assert = require( 'assert' ); 
module.exports = require( 'simple-ioc' )
	.getContainer()
    .registerInjectable( {
    	module1: function( pub ) {
            pub.value = 'val1';
        },
        module2: function( pub ) {
        	pub.value = 'val2';
        }
    } )
    .inject( function( assert, module1, module2 ) {
    	assert.equal( module1.value, 'val1' );
    	assert.equal( module2.value, 'val2');
    } );

---

### injectAfterResolveAll( fn ) Specify a function that is injected after resolve all is complete, can be used in, for example, system tests.

Arguments

• fn function to inject

Returns

The container.

Remarks

None.

Example

// ./index.js
var assert = require( 'assert' ); 
module.exports = require( 'simple-ioc' )
	.getContainer()
    .registerInjectable( {
    	module1: function( pub, callback ) {
            setTimeout( function() {
            	pub.value = 'val1';
            	callback();
            }, 500 );
        },
        module2: function( pub ) {
        	pub.value = 'val2';
        }
    } )
    .resolveAllAndInject( function( assert, module1, module2 ) {
		console.log( 'Application started' );
    } );

// ./tests/system/test.js
var container = require( '../../../index.js' )
	.injectAfterResolveAll( function( module1 ) {
    	assert.equal( module1.value, 'val1' );
    } );

---

### registerResolvedIfSetting ( settingKey, name, instance ) Registers an resolved component if settings indicates it should be registered. Used for example when a component only should be used in certain environments.

Arguments

• settingKey - the dot notated key in settings (true/false)
• name - the identifying name of the component
• fn - the resolved component

Returns

The container.

Remarks

None.

Example

var container = require( 'simple-ioc' ).getContainer()
	.setSettings( {
		use: {
			adapter: true
		}
	} )
	.registerResolvedIfSetting( 'use.adapter', 'componentName', require( 'someResolvedComponent' ) ); // Will register required component as resolved

---

### registerInjectableIfSetting( settingKey, name, fn ) Registers a injectable component if settings indicates it should be registered. Used for example when a component only should be used in certain environments.

Arguments

• settingKey - the dot notated key in settings (true/false)
• name - the identifying name of the component
• fn - the injectable function

Returns

The container.

Remarks

None.

Example

var container = require( 'simple-ioc' ).getContainer()
	.setSettings( {
		use: {
			adapter: true
		}
	} )
	.registerInjectableIfSetting( 'use.adapter', 'componentName', require( 'someInjectableComponent' ) ); // Will register required component as injectable

---

### autoRegisterPathInSetting( settingKey ) Auto registers path that is specified in the settings, can be used for example when different adapers are used in development and production.

Arguments

• settingKey - the dot notated key in settings that referes to the path

Returns

The container.

Remarks

None.

Example

var container = require( 'simple-ioc' ).getContainer()
	.setSettings( {
		use: {
			adapter: '/myPath/adaper1'
		}
	} )
	.autoRegisterPathInSetting( 'use.adapter' ); // Will auto register all files in the path '/myPath/adaper1'

---

### removeRegistered( name ) Removes an injectable unresolved component from the container, main purpose is to change behaviour in system-tests after an application is started with 'resolveAllAndInject'.

Arguments

• name - the identifying name of the component to remove from the container

Returns

The container.

Remarks

Only injectable components that has not yet been resolved can be removed.

Example

// ./index.js
var assert = require( 'assert' ); 
module.exports = require( 'simple-ioc' )
    .getContainer()
    .registerInjectable( {
        module1: function( pub, callback ) {
            setTimeout( function() {
                pub.value = 'val1';
                callback();
            }, 500 );
        },
        module2: function( pub, module1 ) {
            pub.value = module1.value;
        }
    } )
    .resolveAllAndInject( function() {
        console.log( 'Application started' );
    } );

// ./tests/system/test.js
var container = require( '../../../index.js' )
    .removeRegistered( 'module1' )
    .registerResolved( {
        module1: { value: 'newVal1' }
    } )
    .injectAfterResolveAll( function( assert, module2 ) {
        assert.equal( module2.value, 'newVal1' );
    } );

### export( name ) EXPERIMENTAL! Used to export components from one application that has started with resolveAllAndInject

Arguments

• name - the identifying name of the component to export

Returns

An injectable functions with that callbacks the component

Remarks

None.

Example

// ./index.js
var assert = require( 'assert' ); 
module.exports = require( 'simple-ioc' )
    .getContainer()
    .registerInjectable( {
        moduleFromOtherApplication: require( 'otherApplication' ).export( 'moduleFromOtherApplication' )
    } )
    .resolveAllAndInject( function( moduleFromOtherApplication ) {
        console.log( 'Application started' );
    } );

---

## log The ioc has a built in logger that can be used externaly as well. The logger builds a logObject that looks like this:

{
	level: level,
	message: message,
	data: data,
	component: parentName,
	...environment variables specified in the settings
}

In the log-settings you can specify envronment values that you would like to include in the log-objects

includeEnvironmentVariables: { enviro: 'ENV_NAME' }
// Would include ENV_NAME as "enviro"

---

### fatal( message, [ data ] )

Arguments

• message log message
• data optional dataobject that will be in the output

Returns

Undefined.

Remarks

After the log is written system.exit() is automatically called.

Example

log.fatal( 'Fatal error occured, not recoverable', err ); // Application will exit

---

### error( message, [ data ] )

Arguments

• message log message
• data optional dataobject that will be in the output

Returns

Undefined.

Remarks

None.

Example

log.error( 'Error occured, request probably fails', err );

---

### warning( message, [ data ] )

Arguments

• message log message
• data optional dataobject that will be in the output

Returns

Undefined.

Remarks

None.

Example

log.warning( 'Unexpected behaviour, recoverable, request will probably not fail', err );

---

### info( message, [ data ] )

Arguments

• message log message
• data optional dataobject that will be in the output

Returns

Undefined.

Remarks

None.

Example

log.info( 'Setup was successful' );

---

### debug( message, [ data ] )

Arguments

• message log message
• data optional dataobject that will be in the output

Returns

Undefined.

Remarks

None.

Example

log.debug( 'Incomming request', req );

---

### trace( message, [ data ] )

Arguments

• message log message
• data optional dataobject that will be in the output

Returns

Undefined.

Remarks

None.

Example

log.trace( 'Session resolved', session );

---

### getEntries( [ componentName ] ) If the memoryJson writer is used it is possible to iterate through the logs that have been written. This might be useful in tests.

Arguments

• componentName optional, name of component to get logs from

Returns

Undefined.

Remarks

None.

Example

log.info( 'Incomming request' );
assert.equal( log.getEntries()[ 0 ].message, 'Incomming request' );

---

### reset() If the memoryJson writer is used it is possible to reset the log-store.

Arguments

None.

Returns

Undefined.

Remarks

None.

Example

log.info( 'Incomming request' );
log.reset();
assert.equal( log.getEntries()[ 0 ].length, 0 );

---

## errRerouter( callback, successFn ) Simple ioc offers a small helper function to route errors to calling component, this component is optional to use, but might be handy in some situations.

Arguments

• callback the callback to send error to
• successFn function to call if first argument evaluates as false.

Returns

The rerouter

remarks

None.

Example

module.exports = function( pub, errRerouter, someErrorThrowingAsyncComponent ) {
    pub.get = function( callback ) {
        someErrorThrowingAsyncComponent.get( errRerouter( callback, function( data ) {
            callback( undefined, data.someData ); // Just implement "happy-flow"
        } ) );
    };
};

Is equivalent to

module.exports = function( pub, someErrorThrowingAsyncComponent ) {
    pub.get = function( callback ) {
        someErrorThrowingAsyncComponent.get( function( err, data ) {
            if( err )
                callback( err ); // Check for error needed
            else
                callback( undefined, data.someData );
        } );
    };
};