Fire onComplete signal with zero length resources list

[koutoftimer]

Suppose we have app structure where each "stage's child" has its own resource list. It this case to load all required resources we need to call loader.add on the list of unknown length and in case of zero length list there is no other choice to track resource loading rather additional checks on empty list manually.

It is a more intuitive way to fire onComplete signal when all resources are loaded or resource list is empty.

Related to #98 , because subresources by themselves could have zero assert list, but their children could have a lot of required assets.

Example (live code snippet):

class GameScene extends BaseScene {
    loadResources() {
        // Suppose we want to make sure that all resources are loaded to continue.
        // Lets return a promise that will call `resolve`.
        return new Promise((resolve, reject) => {
            // Collect all required resources for current scene.
            let resourcesList = this.children
                .map((child) => child['resourcesList'] || [])
                .reduce((a, c) => a.concat(c))

            // Check resources lenght and if it is not empty start loading process
            if (resourcesList.lenght) {
                // Add `onComplete` handler to call `resolve` when all resources will
                // be loaded
                loader.add(resourcesList)
                    .load(() => {
                        // DUPLICATE
                        this.setup()
                        resolve()
                    })

            } 

            // else just call resolve
            else {
                // DUPLICATE
                this.setup()
                resolve()
            }
        })
    }
}

[Chad Engler]

To make sure I understand what you are asking for: you want onComplete to fire if you call .load() without having called .add() at all before?

[koutoftimer]

If .add receives an array, I'd like to have this

loadResources() {
    return new Promise((resolve, reject) => { 
        loader.add(this.resources)
            .load((loader, resources) => {
                resolve(loader, resources)
            })
    })
}

to work like that

loadResources() {
    return new Promise((resolve, reject) => { 
        let resources = this.resources
        resources.length == 0
            ? resolve(null, null)
            : loader.add(resources).load((loader, resources) => {
                resolve(loader, resources)
            })
    })
}

without ternary operator with empty list of zero length, so .add() should be able to fire onComplete event on execution of the following code loader.add([]).load(() => { }). As you can see, .add is called before .load but function inside it didn't get called.

[Chad Engler]

Makes sense, can you take a look at #107 and see if that fixes your issue? I added some tests that pass, but want to make sure I am hitting your use case properly.

Thanks!

[koutoftimer]

I'm using resource-loader as part of pixi.js and I'm lazy to rebuilt it with your changes, right now.

I'm not confident about what is async.queue, but logic is absolutely right. I suppose Queue.idle is a getter that returns true if the queue is empty.

Thank you for so fast response and pull request, especially on holidays and Happy New Year.

[Chad Engler]

I'm not confident about what is async.queue, but logic is absolutely right. I suppose Queue.idle is a getter that returns true if the queue is empty.

https://github.com/englercj/resource-loader/blob/master/src/async.js#L120-L122

Thank you for so fast response and pull request, especially on holidays and Happy New Year.

No problem, I'll get this merged and released soon.

[Chad Engler]

Closed by 7e09257