Interface Callbacks<T>

``

1.7

​ ````Use callbacks.add() to add new callbacks to a callback list:

// A sample logging function to be added to a callbacks list
var foo = function( value ) {
console.log( "foo: " + value );
};
​
// Another function to also be added to the list
var bar = function( value ) {
console.log( "bar: " + value );
};
​
var callbacks = $.Callbacks();
​
// Add the function "foo" to the list
callbacks.add( foo );
​
// Fire the items on the list
callbacks.fire( "hello" );
// Outputs: "foo: hello"
​
// Add the function "bar" to the list
callbacks.add( bar );
​
// Fire the items on the list again
callbacks.fire( "world" );
​
// Outputs:
// "foo: world"
// "bar: world"

``

1.7

​ ````Use callbacks.disable() to disable further calls to a callback list:

// A sample logging function to be added to a callbacks list
var foo = function( value ) {
console.log( value );
};
​
var callbacks = $.Callbacks();
​
// Add the above function to the list
callbacks.add( foo );
​
// Fire the items on the list
callbacks.fire( "foo" );
// Outputs: foo
​
// Disable further calls being possible
callbacks.disable();
​
// Attempt to fire with "foobar" as an argument
callbacks.fire( "foobar" );
// foobar isn't output

``

1.7

​ ````Use callbacks.disabled() to determine if the callbacks list has been disabled:

// A sample logging function to be added to a callbacks list
var foo = function( value ) {
console.log( "foo:" + value );
};
​
var callbacks = $.Callbacks();
​
// Add the logging function to the callback list
callbacks.add( foo );
​
// Fire the items on the list, passing an argument
callbacks.fire( "hello" );
// Outputs "foo: hello"
​
// Disable the callbacks list
callbacks.disable();
​
// Test the disabled state of the list
console.log ( callbacks.disabled() );
// Outputs: true

``

1.7

​ ````Use callbacks.empty() to empty a list of callbacks:

// A sample logging function to be added to a callbacks list
var foo = function( value1, value2 ) {
console.log( "foo: " + value1 + "," + value2 );
};
​
// Another function to also be added to the list
var bar = function( value1, value2 ) {
console.log( "bar: " + value1 + "," + value2 );
};
​
var callbacks = $.Callbacks();
​
// Add the two functions
callbacks.add( foo );
callbacks.add( bar );
​
// Empty the callbacks list
callbacks.empty();
​
// Check to ensure all callbacks have been removed
console.log( callbacks.has( foo ) );
// false
console.log( callbacks.has( bar ) );
// false

``

1.7

​ ````Use callbacks.fire() to invoke the callbacks in a list with any arguments that have been passed:

// A sample logging function to be added to a callbacks list
var foo = function( value ) {
console.log( "foo:" + value );
};
​
var callbacks = $.Callbacks();
​
// Add the function "foo" to the list
callbacks.add( foo );
​
// Fire the items on the list
callbacks.fire( "hello" ); // Outputs: "foo: hello"
callbacks.fire( "world" ); // Outputs: "foo: world"
​
// Add another function to the list
var bar = function( value ){
console.log( "bar:" + value );
};
​
// Add this function to the list
callbacks.add( bar );
​
// Fire the items on the list again
callbacks.fire( "hello again" );
// Outputs:
// "foo: hello again"
// "bar: hello again"

``

1.7

​ ````Use callbacks.fireWith() to fire a list of callbacks with a specific context and an array of arguments:

// A sample logging function to be added to a callbacks list
var log = function( value1, value2 ) {
console.log( "Received: " + value1 + "," + value2 );
};
​
var callbacks = $.Callbacks();
​
// Add the log method to the callbacks list
callbacks.add( log );
​
// Fire the callbacks on the list using the context "window"
// and an arguments array
​
callbacks.fireWith( window, [ "foo","bar" ] );
// Outputs: "Received: foo, bar"

``

1.7

​ ````Use callbacks.fired() to determine if the callbacks in a list have been called at least once:

// A sample logging function to be added to a callbacks list
var foo = function( value ) {
console.log( "foo:" + value );
};
​
var callbacks = $.Callbacks();
​
// Add the function "foo" to the list
callbacks.add( foo );
​
// Fire the items on the list
callbacks.fire( "hello" ); // Outputs: "foo: hello"
callbacks.fire( "world" ); // Outputs: "foo: world"
​
// Test to establish if the callbacks have been called
console.log( callbacks.fired() );

``

1.7

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

// 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

``

1.7

​ ````Use callbacks.lock() to lock a callback list to avoid further changes being made to the list state:

// A sample logging function to be added to a callbacks list
var foo = function( value ) {
console.log( "foo:" + value );
};
​
var callbacks = $.Callbacks();
​
// Add the logging function to the callback list
callbacks.add( foo );
​
// Fire the items on the list, passing an argument
callbacks.fire( "hello" );
// Outputs "foo: hello"
​
// Lock the callbacks list
callbacks.lock();
​
// Try firing the items again
callbacks.fire( "world" );
​
// As the list was locked, no items were called,
// so "world" isn't logged

​ ````Use callbacks.lock() to lock a callback list with "memory," and then resume using the list:

<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>callbacks.lock demo</title>
<script src="https://code.jquery.com/jquery-3.3.1.js"></script>
</head>
<body>
​
<div id="log"></div>
​
<script>
// Simple function for logging results
var log = function( value ) {
$( "#log" ).append( "<p>" + value + "</p>" );
};
​
// Two sample functions to be added to a callbacks list
var foo = function( value ) {
log( "foo: " + value );
};
var bar = function( value ) {
log( "bar: " + value );
};
​
// Create the callbacks object with the "memory" flag
var callbacks = $.Callbacks( "memory" );
​
// Add the foo logging function to the callback list
callbacks.add( foo );
​
// Fire the items on the list, passing an argument
callbacks.fire( "hello" );
// Outputs "foo: hello"
​
// Lock the callbacks list
callbacks.lock();
​
// Try firing the items again
callbacks.fire( "world" );
// As the list was locked, no items were called,
// so "foo: world" isn't logged
​
// Add the foo function to the callback list again
callbacks.add( foo );
​
// Try firing the items again
callbacks.fire( "silentArgument" );
// Outputs "foo: hello" because the argument value was stored in memory
​
// Add the bar function to the callback list
callbacks.add( bar );
​
callbacks.fire( "youHadMeAtHello" );
// Outputs "bar: hello" because the list is still locked,
// and the argument value is still stored in memory
</script>
​
</body>
</html>

``

1.7

​ ````Use callbacks.locked() to determine the lock-state of a callback list:

// A sample logging function to be added to a callbacks list
var foo = function( value ) {
console.log( "foo: " + value );
};
​
var callbacks = $.Callbacks();
​
// Add the logging function to the callback list
callbacks.add( foo );
​
// Fire the items on the list, passing an argument
callbacks.fire( "hello" );
// Outputs "foo: hello"
​
// Lock the callbacks list
callbacks.lock();
​
// Test the lock-state of the list
console.log ( callbacks.locked() );
// true

``

1.7

​ ````Use callbacks.remove() to remove callbacks from a callback list:

// A sample logging function to be added to a callbacks list
var foo = function( value ) {
console.log( "foo: " + value );
};
​
var callbacks = $.Callbacks();
​
// Add the function "foo" to the list
callbacks.add( foo );
​
// Fire the items on the list
callbacks.fire( "hello" );
// Outputs: "foo: hello"
​
// Remove "foo" from the callback list
callbacks.remove( foo );
​
// Fire the items on the list again
callbacks.fire( "world" );
​
// Nothing output as "foo" is no longer in the list