[Proto-Scripty] Re: PeriodicalExecuter Error: this.callback is not a function (prototype.js Line 308)
Hi,
When I change the line into new PeriodicalExecuter
(myobject.unknownMethod(), 3);, firebug at once states correctly that
this function doesn't exist, which is right.
And if it did exist, it would execute once, immediately, and the
PeriodicalExecuter would fail three seconds later. This line of code:
new PeriodicalExecuter(obj.method(), 3);
...like any other function call runs obj.method _immediately_ and
passes the return value of the method into the PeriodicalExecuter
constructor. Unless the method returns a function reference, that's
not going to work.
You probably want to do this:
new PeriodicalExecuter(obj.method.bind(obj), 3);
Note that we are *not* calling method here; we're calling bind and
telling it to return a function that, when called, will call
obj.method.
If you're not using an object method, just a function, you don't need
bind:
new PeriodicalExecuter(someFunction, 3);
Note, again, that we are not *calling* someFunction there (there are
no parens after it), we're just passing a reference to it into the
constructor.
[1] http://prototypejs.org/api/periodicalExecuter
[2] http://prototypejs.org/api/function/bind
HTH,
--
T.J. Crowder
tj / crowder software / com
Independent Software Engineer, consulting services available
On Aug 7, 1:30 am, Schweitzer lul...@gmx.de wrote:
Hi there!
Got an error with Prototypes PeriodicalExecuter() (Version 1.6.0.3):
When I use the verified (http://www.prototypejs.org/api/
periodicalExecuter) new PeriodicalExecuter(myobject.testMethod(),
3);, everything seems fine (no error in Firebug etc) but after 3
Seconds an error this.callback is not a function [...]/prototype.js
Line 308 appears. testMethod was not started.
The line new PeriodicalExecuter(function() { alert(test); }, 3);
works when written instead.
When I change the line into new PeriodicalExecuter
(myobject.unknownMethod(), 3);, firebug at once states correctly that
this function doesn't exist, which is right.
Now I wonder about why this error appears. As you may imagine,
testMethod() is part of an Object, but the error appears outside as
inside the initialize()-function of the Class created by Class.create
(). Even outside the class. The used testMethod() seems to exist
nonetheless.
I would like to read any hint or maybe solution to this problem,
please feel free to ask for more information, too.
Schweitzer
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[Proto-Scripty] Re: PeriodicalExecuter Error: this.callback is not a function (prototype.js Line 308)
Thank you very much for responding that fast and clear. In fact you
are right, I misinterpreted the usage.
Thanks to you, this file is closed now ;)
On 7 Aug., 10:51, T.J. Crowder t...@crowdersoftware.com wrote:
Hi,
When I change the line into new PeriodicalExecuter
(myobject.unknownMethod(), 3);, firebug at once states correctly that
this function doesn't exist, which is right.
And if it did exist, it would execute once, immediately, and the
PeriodicalExecuter would fail three seconds later. This line of code:
new PeriodicalExecuter(obj.method(), 3);
...like any other function call runs obj.method _immediately_ and
passes the return value of the method into the PeriodicalExecuter
constructor. Unless the method returns a function reference, that's
not going to work.
You probably want to do this:
new PeriodicalExecuter(obj.method.bind(obj), 3);
Note that we are *not* calling method here; we're calling bind and
telling it to return a function that, when called, will call
obj.method.
If you're not using an object method, just a function, you don't need
bind:
new PeriodicalExecuter(someFunction, 3);
Note, again, that we are not *calling* someFunction there (there are
no parens after it), we're just passing a reference to it into the
constructor.
[1]http://prototypejs.org/api/periodicalExecuter
[2]http://prototypejs.org/api/function/bind
HTH,
--
T.J. Crowder
tj / crowder software / com
Independent Software Engineer, consulting services available
On Aug 7, 1:30 am, Schweitzer lul...@gmx.de wrote:
Hi there!
Got an error with Prototypes PeriodicalExecuter() (Version 1.6.0.3):
When I use the verified (http://www.prototypejs.org/api/
periodicalExecuter) new PeriodicalExecuter(myobject.testMethod(),
3);, everything seems fine (no error in Firebug etc) but after 3
Seconds an error this.callback is not a function [...]/prototype.js
Line 308 appears. testMethod was not started.
The line new PeriodicalExecuter(function() { alert(test); }, 3);
works when written instead.
When I change the line into new PeriodicalExecuter
(myobject.unknownMethod(), 3);, firebug at once states correctly that
this function doesn't exist, which is right.
Now I wonder about why this error appears. As you may imagine,
testMethod() is part of an Object, but the error appears outside as
inside the initialize()-function of the Class created by Class.create
(). Even outside the class. The used testMethod() seems to exist
nonetheless.
I would like to read any hint or maybe solution to this problem,
please feel free to ask for more information, too.
Schweitzer
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Prototype script.aculo.us group.
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