Semantic Modules

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modal.commented.js module.commented.js

¶

Semantic Modules

This is a design pattern for creating UI modules in Semantic

Semantic is unique in that all arbitrary data is a setting. Semantic modules also are self documenting, with module.debug calls serving to explain state, and log performance data. Read more about coding conventions and Read about modules
```
/*
 * # Semantic Module
 * http://github.com/quirkyinc/semantic
 *
 *
 * Copyright 2013 Contributors
 * Released under the MIT license
 * http://opensource.org/licenses/MIT
 */

;(function ( $, window, document, undefined ) {

$.fn.example = function(parameters) {
```
¶

Group

Some properties remain constant across all instances of a module.
```
  var
```
¶

Store a reference to the module group, this can be useful to refer to other modules inside each module
```
    $allModules     = $(this),
```

Preserve selector from outside each scope and mark current time for performance tracking

    moduleSelector  = $allModules.selector || '',
    time            = new Date().getTime(),
    performance     = [],

Preserve original arguments to determine if a method is being invoked

    query           = arguments[0],
    methodInvoked   = (typeof query == 'string'),
    queryArguments  = [].slice.call(arguments, 1),
    returnedValue
  ;

Singular

Iterate over all elements to initialize module

  $allModules
    .each(function() {
      var

Extend settings to merge run-time settings with defaults

        settings        = ( $.isPlainObject(parameters) )
          ? $.extend(true, {}, $.fn.example.settings, parameters)
          : $.extend({}, $.fn.example.settings),

Alias settings object for convenience and performance

        namespace      = settings.namespace,
        error          = settings.error,
        className      = settings.className,

¶

You may also find it useful to alias your own settings
```
        text           = settings.text,
```

Define namespaces for storing module instance and binding events

        eventNamespace  = '.' + namespace,
        moduleNamespace = 'module-' + namespace,

Instance is stored and retreived in namespaced DOM metadata

        instance        = $(this).data(moduleNamespace),
        element         = this,

Cache selectors using selector settings object for access inside instance of module

        $module        = $(this),
        $text          = $module.find(settings.selector.text),

¶

Define private variables which can be used to maintain internal state, these cannot be changed from outside the module closure so use conservatively. Default values are set using a || b syntax
```
        foo            = false,


        module
      ;
```
¶

Module Behavior
```
      module = {
```
¶

Required

Initialize

Initialize attaches events and preserves each instance in html metadata

        initialize: function() {
          module.debug('Initializing module for', element);
          $module
            .on('click' + eventNamespace, module.exampleBehavior)
          ;
          module.instantiate();
        },

        instantiate: function() {
          module.verbose('Storing instance of module');

¶

The instance is just a copy of the module definition, we store it in metadata so we can use it outside of scope, but also define it for immediate use
```
          instance = module;
          $module
            .data(moduleNamespace, instance)
          ;
        },
```

Destroy

Removes all events and the instance copy from metadata

        destroy: function() {
          module.verbose('Destroying previous module for', element);
          $module
            .removeData(moduleNamespace)
            .off(eventNamespace)
          ;
        },

Refresh

Selectors or cached values sometimes need to refreshed

        refresh: function() {
          module.verbose('Refreshing elements', element);
          $module = $(element);
          $text   = $(this).find(settings.selector.text);
        },

Custom

By Event

Sometimes it makes sense to call an event handler by its type if it is dependent on the event to behave properly

        event: {
          click: function(event) {
            module.verbose('Preventing default action');
            if( !$module.hasClass(className.disabled) ) {
              module.behavior();
            }
            event.preventDefault();
          }
        },

By Function

Other times events make more sense for methods to be called by their function if it is ambivalent to how it is invoked

        behavior: function() {
          module.debug('Changing the text to a new value', text);
          if( !module.has.text() ) {
            module.set.text( text);
          }
        },

Vocabulary

Custom methods should be defined with consistent vocabulary some useful terms: “has”, “set”, “get”, “change”, “add”, “remove”

This makes it easier for new developers to get to know your module without learning your schema

        has: {
          text: function(state) {
            module.verbose('Checking whether text state exists', state);
            if( text[state] === undefined ) {
              module.error(error.noText);
              return false;
            }
            return true;
          }
        },

        set: {
          text: function(state) {
            module.verbose('Setting text to new state', state);
            if( module.has.text(state) ) {
              $text
                .text( text[state] )
              ;
              settings.onChange();
            }
          }
        },

¶

Standard

Setting

Module settings can be read or set using this method

Settings can either be specified by modifying the module defaults, by initializing the module with a settings object, or by changing a setting by invoking this method $(.foo').example('setting', 'moduleName');

        setting: function(name, value) {
          if( $.isPlainObject(name) ) {
            $.extend(true, settings, name);
          }
          else if(value !== undefined) {
            settings[name] = value;
          }
          else {
            return settings[name];
          }
        },

Internal

Module internals can be set or retrieved as well $(.foo').example('internal', 'behavior', function() { // do something });

        internal: function(name, value) {
          if( $.isPlainObject(name) ) {
            $.extend(true, module, name);
          }
          else if(value !== undefined) {
            module[name] = value;
          }
          else {
            return module[name];
          }
        },

Debug

Debug pushes arguments to the console formatted as a debug statement

        debug: function() {
          if(settings.debug) {
            if(settings.performance) {
              module.performance.log(arguments);
            }
            else {
              module.debug = Function.prototype.bind.call(console.info, console, settings.name + ':');
              module.debug.apply(console, arguments);
            }
          }
        },

Verbose

Calling verbose internally allows for additional data to be logged which can assist in debugging

        verbose: function() {
          if(settings.verbose && settings.debug) {
            if(settings.performance) {
              module.performance.log(arguments);
            }
            else {
              module.verbose = Function.prototype.bind.call(console.info, console, settings.name + ':');
              module.verbose.apply(console, arguments);
            }
          }
        },

Error

Error allows for the module to report named error messages, it may be useful to modify this to push error messages to the user. Error messages are defined in the modules settings object.

        error: function() {
          module.error = Function.prototype.bind.call(console.error, console, settings.name + ':');
          module.error.apply(console, arguments);
        },

Performance

This is called on each debug statement and logs the time since the last debug statement.

        performance: {
          log: function(message) {
            var
              currentTime,
              executionTime,
              previousTime
            ;
            if(settings.performance) {
              currentTime   = new Date().getTime();
              previousTime  = time || currentTime;
              executionTime = currentTime - previousTime;
              time          = currentTime;
              performance.push({
                'Element'        : element,
                'Name'           : message[0],
                'Arguments'      : [].slice.call(message, 1) || '',
                'Execution Time' : executionTime
              });
            }
            clearTimeout(module.performance.timer);
            module.performance.timer = setTimeout(module.performance.display, 100);
          },
          display: function() {
            var
              title = settings.name + ':',
              totalTime = 0
            ;
            time = false;
            clearTimeout(module.performance.timer);
            $.each(performance, function(index, data) {
              totalTime += data['Execution Time'];
            });
            title += ' ' + totalTime + 'ms';
            if(moduleSelector) {
              title += ' \'' + moduleSelector + '\'';
            }
            if( (console.group !== undefined || console.table !== undefined) && performance.length > 0) {
              console.groupCollapsed(title);
              if(console.table) {
                console.table(performance);
              }
              else {
                $.each(performance, function(index, data) {
                  console.log(data['Name'] + ': ' + data['Execution Time']+'ms');
                });
              }
              console.groupEnd();
            }
            performance = [];
          }
        },

Invoke

Invoke is used to match internal functions to string lookups. $('.foo').example('invoke', 'set text', 'Foo') Method lookups are lazy, looking for many variations of a search string For example ‘set text’, will look for both setText : function(){}, set: { text: function(){} } Invoke attempts to preserve the ‘this’ chaining unless a value is returned. If multiple values are returned an array of values matching up to the length of the selector is returned

        invoke: function(query, passedArguments, context) {
          var
            maxDepth,
            found,
            response
          ;
          passedArguments = passedArguments || queryArguments;
          context         = element         || context;
          if(typeof query == 'string' && instance !== undefined) {
            query    = query.split(/[\. ]/);
            maxDepth = query.length - 1;
            $.each(query, function(depth, value) {
              var camelCaseValue = (depth != maxDepth)
                ? value + query[depth + 1].charAt(0).toUpperCase() + query[depth + 1].slice(1)
                : query
              ;
              if( $.isPlainObject( instance[value] ) && (depth != maxDepth) ) {
                instance = instance[value];
              }
              else if( $.isPlainObject( instance[camelCaseValue] ) && (depth != maxDepth) ) {
                instance = instance[camelCaseValue];
              }
              else if( instance[value] !== undefined ) {
                found = instance[value];
                return false;
              }
              else if( instance[camelCaseValue] !== undefined ) {
                found = instance[camelCaseValue];
                return false;
              }
              else {
                module.error(error.method, query);
                return false;
              }
            });
          }
          if ( $.isFunction( found ) ) {
            response = found.apply(context, passedArguments);
          }
          else if(found !== undefined) {
            response = found;
          }

Invocation response

If a user passes in multiple elements invoke will be called for each element and the value will be returned in an array For example $('.things').example('has text') with two elements might return [true, false] and for one element true

          if($.isArray(returnedValue)) {
            returnedValue.push(response);
          }
          else if(returnedValue !== undefined) {
            returnedValue = [returnedValue, response];
          }
          else if(response !== undefined) {
            returnedValue = response;
          }
          return found;
        }
      };

¶

Determining Intent
¶

This is where the actual action occurs. $(‘.foo’).module(‘set text’, ‘Ho hum’); If you call a module with a string parameter you are most likely trying to invoke a function
```
      if(methodInvoked) {
        if(instance === undefined) {
          module.initialize();
        }
        module.invoke(query);
      }
```

if no method call is required we simply initialize the plugin, destroying it if it exists already

      else {
        if(instance !== undefined) {
          module.destroy();
        }
        module.initialize();
      }
    })
  ;

  return (returnedValue !== undefined)
    ? returnedValue
    : this
  ;

};

¶

Settings

It is necessary to include a settings object which specifies the defaults for your module
```
$.fn.example.settings = {
```
¶

Required

Used in debug statements to refer to the module itself
```
  name  : 'Example Module',
```
¶

Whether debug content should be outputted to console
```
  debug       : true,
```
¶

Whether extra debug content should be outputted
```
  verbose     : false,
```
¶

Whether to track performance data
```
  performance : false,
```
¶

A unique identifier used to namespace events,and preserve the module instance
```
  namespace   : 'example',
```
¶

Optional

Selectors used by your module

  selector    : {
    example : '.example'
  },

Error messages returned by the module

  error: {
    noText : 'The text you tried to display has not been defined.',
    method : 'The method you called is not defined.'
  },

Class names which your module refers to

  className   : {
    disabled : 'disabled'
  },

¶

Metadata attributes stored or retrieved by your module. $('.foo').data('value');
```
  metadata: {
    text: 'text'
  },
```
¶

Callbacks

Callbacks are often useful to include in your settings object
```
  onChange     : function() {},
```

Definition Specific

You may also want to include settings specific to your module’s function

  text: {
    hover : 'You are hovering me now',
    click : 'You clicked on me'
  }

};


})( jQuery, window , document );