RemoveListener for Spine animations

[Outfire]

RemoveListener is works, but only in one way:

let spine // our spine animation
let log = () => console.log('nonsense');
let listener = {complete: log};

spine.state.addListener(listener);

And removes it like

spine.state.removeListener(listener);

It does not work if i do it like this:

let spine //our spine animation
let log = () => console.log('nonsense');

spine.state.addListener({complete: log});
// trying to remove
spine.state.addListener(log);
// or just like this
spine.state.addListener({complete: log});

Works fine if add and remove only the same object, but its long way.
Is there another way to do this?

 

[ivan.popelyshev]

I like the idea.

This is the part in pixi-spine: https://github.com/pixijs/pixi-spine/blob/master/src/core/AnimationState.ts#L561

This is upstream, spine-ts: https://github.com/EsotericSoftware/spine-runtimes/blob/3.6/spine-ts/core/src/AnimationState.ts#L561

You can hack pixi-spine:

PIXI.spine.core.AnimationState.prototype.removeListener = function (...) { }

Please make PR or at least give me the code with the behaviour you want. I'm all hands for enhancing pixi-spine, we already have some things that distinguish us from spine-ts.

[Outfire]

Need some time to think about it.

I think about "spine.removeListener({complete: log})"
But we can add "log" twice or more in one "complete", and then our removeListener must remove all "log"s in "complete" or just the last one.

Maybe it is possible to do like in DOM addEventListener, when you add new listener on the same event with the same listener name it removes old one and push new one instead of it .

[ivan.popelyshev]

"removes old one" is bad idea because that'll break spine-ts compatibility. You can add your own version with add/remove under different name.

[Outfire]

Yes, it is my problem if I  forget that I already have listener with the same name.

I think variant - "spine.removeListener({complete: 'log'})" (event name and listener name) - is the best way and pretty obvious one.

And "spine.removeListener({complete: ['log', 'update'], start: 'playSound'})" to remove multiple events. 

Perhaps is it possible to upgrade  clearListeners function , so it takes event name as an argument and as result removes all listeners subscribed to this particular event?

[ivan.popelyshev]

OK, try to hack pixi-spine, and if it works for you and satisfies me, i'll add it to the lib

I remind you that canonical spine runtimes does not have this feature, so it'll be sugar for pixi-spine.

[Outfire]

I considered on how  to implement function to remove listeners, and here is the result.

The following code can be used to remove function from particular listener.

PIXI.spine.core.AnimationState.prototype.removeListenersByName = function (findListener) {
    this.listeners.forEach( listener => {
        for(let currentListenerName in listener) {
            for(let findListenerName in findListener) {
                if (currentListenerName === findListenerName 
                && listener[currentListenerName].name === findListener[findListenerName]) {
                    if(Object.keys(listener).length === 1) {
                        this.removeListener(listener);
                    } else {
                        delete listener[currentListenerName]
                    }
                }
            }
        }
    })
}

spine.addListener({ complete: foo, end: bar })

removeListenersByName({ complete: 'foo' })
removeListenersByName({ complete: 'foo', end: 'bar' })

But this solution has one problem.

spine.addListener({ complete: foo.bind(this)})

Then  listeners[0].complete.name will be 'bound foo', not 'foo'.This problem can be solved in the following way.

PIXI.spine.core.AnimationState.prototype.isBounded = function (listenerName, findName) {
    let splited = listenerName.split(' ');

    if (splited.length === 1) {
        return false;
    }

    return splited[0] === 'bound' && splited[1] === findName
}

PIXI.spine.core.AnimationState.prototype.removeListenersByName = function (findListener) {
    this.listeners.forEach( listener => {
        for(let currentListenerName in listener) {
            for(let findListenerName in findListener) {
                if (currentListenerName === findListenerName) {
                    let currentName = listener[currentListenerName].name;
                    let findName = findListener[findListenerName];

                    if (this.isBounded(currentName, findName)) {
                        findName = 'bound ' + findName;
                    }

                    if (currentName === findName) {
                        if(Object.keys(listener).length === 1) {
                            this.removeListener(listener);
                        } else {
                            delete listener[currentListenerName]
                        }
                    }
                }
            }
        }
    })
};

Some other issue can appear.

spine.addListener({complete: () => console.log('something') });

Here listeners[0].complete.name will be 'complete', as the name of the listener, to which function it was bound.
But it's just information.

To remove all functions from particular listener.

PIXI.spine.core.AnimationState.prototype.clearListenersByName = function (listenerName) {
    this.listeners.forEach( listener => {
        for(let key in listener) {
            if (key === listenerName) {
                if(Object.keys(listener).length === 1) {
                    this.removeListener(listener);
                } else {
                    delete listener[key]
                }
            }
        }
    })
}

spine.addListener({ complete: foo, end: bar })
spine.addListener({ complete: foo})

clearListenersByName('complete')

That is the result of my small expierence in js.