How can I check if a jQuery plugin is loaded

Question

Is there any way to check if a particular plugin is available   Imagine that you are developing a plugin that depends on another plugin being loaded   For example I want the jQuery Validation plugin to use the dateJS library to check if a given date is valid  What would be the best way to detect  in the jQuery Valdation plugin if the dateJS was available

User · Accepted Answer

Generally speaking  jQuery plugins are namespaces on the jQuery scope  You could run a simple check to see if the namespace exists    if jQuery   pluginName           run plugin dependent code      dateJs however is not a jQuery plugin  It modifies extends the javascript date object  and is not added as a jQuery namespace  You could check if the method you need exists  for example    if Date today            Use the dateJS today   method      But you might run into problems where the API overlaps the native Date API

User · Answer

Run this in your browser console of choice   if jQuery   pluginName  console log  bonjour      If the plugin exists it will print out  bonjour  as a response in your console

User · Answer

I would strongly recommend that you bundle the DateJS library with your plugin and document the fact that you ve done it   Nothing is more frustrating than having to hunt down dependencies   That said  for legal reasons  you may not always be able to bundle everything   It also never hurts to be cautious and check for the existence of the plugin using Eran Galperin s answer

User · Answer

I would strongly recommend that you bundle the DateJS library with your plugin and document the fact that you ve done it   Nothing is more frustrating than having to hunt down dependencies   That said  for legal reasons  you may not always be able to bundle everything   It also never hurts to be cautious and check for the existence of the plugin using Eran Galperin s answer

User · Answer

I would strongly recommend that you bundle the DateJS library with your plugin and document the fact that you ve done it   Nothing is more frustrating than having to hunt down dependencies   That said  for legal reasons  you may not always be able to bundle everything   It also never hurts to be cautious and check for the existence of the plugin using Eran Galperin s answer

User · Answer

To detect jQuery plugins I found more accurate to use the brackets   if jQuery   pluginName          run plugin dependent code

User · Answer

To detect jQuery plugins I found more accurate to use the brackets   if jQuery   pluginName          run plugin dependent code

User · Answer

This sort of approach should work   var plugin exists   true   try        some code that requires that plugin here   catch err      plugin exists   false

User · Answer

This sort of approach should work   var plugin exists   true   try        some code that requires that plugin here   catch err      plugin exists   false

User · Answer

for the plugins that doesn t use fn namespace  for example pnotify   this works   if   pluginname        alert  plugin loaded      else       alert  plugin not loaded        This doesn t work   if   fn pluginname

User · Answer

jQuery has a method to check if something is a function  if    isFunction   fn dateJS           your code using the plugin     API reference  https   api jquery com jQuery isFunction

User · Answer

for the plugins that doesn t use fn namespace  for example pnotify   this works   if   pluginname        alert  plugin loaded      else       alert  plugin not loaded        This doesn t work   if   fn pluginname

User · Answer

If we re talking about a proper jQuery plugin  one that extends the fn namespace   then the proper way to detect the plugin would be   if typeof   fn pluginname      undefined             Or because every plugin is pretty much guaranteed to have some value that equates to true  you can use the shorter  if    fn pluginname            BTW  the   and jQuery are interchangable  as the odd-looking wrapper around a plugin demonstrates    function                jQuery     the closure   function                  is followed immediately by a call to that closure  passing  jQuery as the parameter   jQuery    the   in the closure is set equal to jQuery

User · Answer

If we re talking about a proper jQuery plugin  one that extends the fn namespace   then the proper way to detect the plugin would be   if typeof   fn pluginname      undefined             Or because every plugin is pretty much guaranteed to have some value that equates to true  you can use the shorter  if    fn pluginname            BTW  the   and jQuery are interchangable  as the odd-looking wrapper around a plugin demonstrates    function                jQuery     the closure   function                  is followed immediately by a call to that closure  passing  jQuery as the parameter   jQuery    the   in the closure is set equal to jQuery

User · Answer

I would strongly recommend that you bundle the DateJS library with your plugin and document the fact that you ve done it   Nothing is more frustrating than having to hunt down dependencies   That said  for legal reasons  you may not always be able to bundle everything   It also never hurts to be cautious and check for the existence of the plugin using Eran Galperin s answer

User · Answer

jQuery has a method to check if something is a function  if    isFunction   fn dateJS           your code using the plugin     API reference  https   api jquery com jQuery isFunction

User · Answer

This sort of approach should work   var plugin exists   true   try        some code that requires that plugin here   catch err      plugin exists   false

User · Answer

Run this in your browser console of choice   if jQuery   pluginName  console log  bonjour      If the plugin exists it will print out  bonjour  as a response in your console

User · Answer

This sort of approach should work   var plugin exists   true   try        some code that requires that plugin here   catch err      plugin exists   false

[jquery] How can I check if a jQuery plugin is loaded?

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