TypeScript - Backing store support

[sebastienlevert]

No description provided.

[baywet]

To restore backing store capabilities since we migrated to interfaces we probably need the do the following:

1. in abstractions implement IBackedModel with a proxy. That proxy would take an IBackingStore as a constructor parameter and route calls to the backing store accordingly.
2. there might not actually be any changes needed to the generation work at this point (or we should remove the backing store assignment from the model constructore/factory)
3. in the serialization library instantiate the implementation from point 1 here when the backing store is in use (we could add a constructor parameter/readonly field in all parseNode implementations, and that field would be set by the respective factory. In turns the factory could have a property (getter/setter) in the ParseNodeFactory interface, which in turns would be set by the proxy factory )

[koros]

This is a rough draft of how to accomplish the task:

on the abstraction library I'll have the following classes:

export interface IBackedModel {
  /**
   * Gets the store that is backing the model.
   */
  backingStore: BackingStore;
}

class BackedModel implements IBackedModel {
  private backingStore: BackingStore;

  constructor(backingStore: BackingStore) {
    this.backingStore = backingStore;
  }
}

NB: the other classes e.g. InMemoryBackingStore and factory have been omitted, Once that is set up the generator should then generate a model interface (same as current) and a class implementation that extends a BackedModel above and implements the respective interface e.g.

// Generated code
export interface Foo extends Entity, Parsable {
  name?: string | undefined;
}

export class FooBackedModel extends BackedModel implements Foo {
  get name(): string | undefined {
    return this.backingStore.get(name);
  }
  set name(value: string | undefined) {
    this.backingStore.name = value;
  }
}

[koros]

@baywet let me know if the above steps need any changes

[baywet]

this would require people to use classes again, which we'd like to avoid.
What if we designed in the abstractions a proxy, that implements BackedModel using the provided backing store (singleton factory)?
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy

[sebastienlevert]

Adding @gavinbarron for more insights and potentially workshopping with @koros