Reviving async nested objects causes missing values

[lordofthelake]

When trying to revive custom objects that have as properties other custom objects, if the reviver functions are asynchronous, the outer object's reviver doesn't receive the nested revived value as an argument immediately, but it does after a timeout.

Simplified example:

class CustomObject { 
	constructor(value) {
		this.value = value;
	}
}

class CustomObjectWithNestedObject {
	constructor(custom) {
		this.custom = custom
	}
}

const tson = new Typeson().register([{
	CustomObject: {
		test: (v) => v instanceof CustomObject,
		replaceAsync: (v) => Typeson.Promise.resolve(v.value),
		reviveAsync: (v) => Typeson.Promise.resolve(new CustomObject(v))
	},
	CustomObjectWithNestedObject: {
		test: (v) => v instanceof CustomObjectWithNestedObject,
		replaceAsync: (v) => Typeson.Promise.resolve({ custom: v.custom }),
		reviveAsync: (v) => Typeson.Promise.resolve(new CustomObjectWithNestedObject(v.custom))
	}
}])

const custom = new CustomObject("Hello")
const customNested = new CustomObjectWithNestedObject(custom);

tson.encapsulateAsync(customNested)
	.then(encapsulated => tson.reviveAsync(encapsulated))
	.then(revived => console.log(revived.customNested)) // => undefined

Interestingly, when rewriting CustomObjectWithNestedObject's reviver using a setTimeout, the property appears, making the problem look like a race condition:

		// ...
		// This works! 
		reviveAsync: (v) => new Typeson.Promise((resolve, reject) => {
			setTimeout(() => {
				// By the time this is executed, v.custom appears on the object!
				resolve(new CustomObjectWithNestedObject(v.custom))
			}, 0);
		})

I have created a CodeSandbox with a reproduction here, with tests extracted from my code: https://codesandbox.io/s/typeson-async-bug-reproduction-prpp9

I hope this can be fixed soon, as this is an otherwise great library :)

[brettz9]

Thanks for your encouragement of the project. I'd like to help, but I'm afraid I have too much on my plate at this time, but I should be able to find time to review a PR if you might be able to take a closer look. Note that the typeson proper codebase is fairly small, so though it can be a little dizzying to track (and the reason why I haven't gotten to #11 as well--which incidentally sounds like it could be similar if not a dupe), it should be doable with some focused time (and probably more importantly, enough forethought on how such nesting needs to work).