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This article mainly explains "when to use flags". The content in the article is simple and clear, easy to learn and understand. Please follow the editor's train of thought to study and learn "when to use flags".

Possible flags: (available flags:)

Once: make sure the callback list only executes (.fire ()) once (like a deferred Deferred).

Memory: keep the previous value and immediately invoke any callback (like a deferred Deferred) with the latest value added to the list.

Unique: make sure you can only add one callback at a time (so there are no duplicate callbacks in the list).

StopOnFalse: interrupts the call when a callback returns false

By default, the callback list can be triggered multiple times as in the callback list of events.

For an example of how flags should be used ideally, see below:

$.Callboxes ("once"):

Var callbacks = $.Callboxes ("once")

Callbacks.add (fn1)

Callbacks.fire ("foo")

Callbacks.add (fn2)

Callbacks.fire ("bar")

Callbacks.remove (fn2)

Callbacks.fire ("foobar")

/ *

Output:

Foo

* /

$.Callboxes ("memory"):

Var callbacks = $.Callboxes ("memory")

Callbacks.add (fn1)

Callbacks.fire ("foo")

Callbacks.add (fn2)

Callbacks.fire ("bar")

Callbacks.remove (fn2)

Callbacks.fire ("foobar")

/ *

Output:

Foo

Fn2 says:foo

Bar

Fn2 says:bar

Foobar

* /

$.Callboxes ("unique"):

Var callbacks = $.Callboxes ("unique")

Callbacks.add (fn1)

Callbacks.fire ("foo")

Callbacks.add (fn1); / / repeat addition

Callbacks.add (fn2)

Callbacks.fire ("bar")

Callbacks.remove (fn2)

Callbacks.fire ("foobar")

/ *

Output:

Foo

Bar

Fn2 says:bar

Foobar

* /

$.Callboxes ("stopOnFalse"):

Function fn1 (value) {

Console.log (value)

Return false

}

Function fn2 (value) {

Fn1 ("fn2 says:" + value)

Return false

}

Var callbacks = $.Callboxes ("stopOnFalse")

Callbacks.add (fn1)

Callbacks.fire ("foo")

Callbacks.add (fn2)

Callbacks.fire ("bar")

Callbacks.remove (fn2)

Callbacks.fire ("foobar")

/ *

Output:

Foo

Bar

Foobar

* /

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