callbacks.has()

jQuery

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callbacks.has()

Categories: Callbacks Object

callbacks.has( callback ) Returns: Boolean

Description: Determine whether a supplied callback is in a list

  • version added: 1.7callbacks.has( callback )

    • callback
      Type: Function()
      The callback to search for.

Example:

Use callbacks.has() to check if a callback list contains a specific callback:

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                                        // a sample logging function to be added to a callbacks list
                                      
                                    

                                  

                                  

                                    

                                      var foo = function( value1, value2 ) {
                                    

                                  

                                  

                                    

                                        console.log( "Received: " + value1 + "," + value2 );
                                    

                                  

                                  

                                    

                                      };
                                    

                                  

                                  

                                    

                                       
                                    

                                  

                                  

                                    

                                      
                                        // a second function which will not be added to the list
                                      
                                    

                                  

                                  

                                    

                                      var bar = function( value1, value2 ) {
                                    

                                  

                                  

                                    

                                        console.log( "foobar" );
                                    

                                  

                                  

                                    

                                      }
                                    

                                  

                                  

                                    

                                       
                                    

                                  

                                  

                                    

                                      var callbacks = $.Callbacks();
                                    

                                  

                                  

                                    

                                       
                                    

                                  

                                  

                                    

                                      
                                        // add the log method to the callbacks list
                                      
                                    

                                  

                                  

                                    

                                      callbacks.add( foo );
                                    

                                  

                                  

                                    

                                       
                                    

                                  

                                  

                                    

                                      
                                        // determine which callbacks are in the list
                                      
                                    

                                  

                                  

                                    

                                       
                                    

                                  

                                  

                                    

                                      console.log( callbacks.has( foo ) );
                                    

                                  

                                  

                                    

                                      
                                        // true
                                      
                                    

                                  

                                  

                                    

                                      console.log( callbacks.has( bar ) );
                                    

                                  

                                  

                                    

                                      
                                        // false
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