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What's the proper way to extend a class in JavaScript if super() needs to wait for a promise?

I wrote an unusual class where I imagined I would be able to load a JSON file to fulfill many of the class's settings and initiate an object accordingly. Except, what happens is the function returns asynchronously while we wait for the filesystem promise (and that's a no-no when extending a class, since super() must be called). Sure, I could go synchronous with the fs call but that seems like a bandaid. What's the right way to go about this?

module.exports = class EntityLoader extends Entity {
    constructor(args, jsonPath="./web/classes/objects/box-pile.json"){
        fs.promises.readFile(jsonPath, 'utf8').then(data => {
            const settings = JSON.parse(data)
            super({
                ...settings,
                ...args
            })
            this.ready.then(() => {
                if (settings.children) settings.children.forEach(childSettings => {
                    this.addChildSprite({...childSettings}).position.set(...childSettings.position[0])
                })
            })
        });
    }
}

Error:

... snip ...\classes\objects\box-pile.js:31 Uncaught ReferenceError: Must call super constructor in derived class before accessing 'this' or returning from derived constructor
    at new EntityLoader ... snip ...
about 4 years ago · Juan Pablo Isaza
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