Type safety for JSON serializable things about fluidframework HOT 9 CLOSED

We have had a lot of discussion about this over the past year, and some things were implemented, like AsJsonable. However, the general consensus has been that this requires too much "fancy type handling" and ultimately is more confusing than helpful.

The current plan is to close this, and possibly remove the things we put in place already with follow up issues.

from fluidframework.

Typescript complains abt. the circular reference if I attempt to support nested arrays like this (e.g., [[[ . ]]]):

export type JsonArray = (JsonPrimitive | JsonObject | JsonArray)[];

(Perhaps @skylerjokiel, @anthony-murphy or @jack-williams have a trick.)

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it can be worked around with more interfaces, but recursive types are coming in typescript 3.7:
https://httptoolkit.tech/blog/5-big-features-of-typescript-3.7/

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Yeah until microsoft/TypeScript#33050 lands it has to be done with an interface:

export interface JsonArray extends Array<JsonPrimitive | JsonObject | JsonArray> {}

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Note: Json introduced in #165

from fluidframework.

The Jsonable definition works well for anonymous objects, but requires casting through 'unknown' in both directions when casting to/from a compatible interface. :-/

    interface ICell {
        text: JsonablePrimitive;
        cache: JsonablePrimitive;
    }

    private loadCell(row: number, col: number): ICell {
        return this.matrix.getItem(row, col) as unknown as ICell;
    }

    private storeCell(row: number, col: number, cell: ICell) {
        return this.matrix.setItems(row, col, [cell as unknown as Jsonable]);
    }

from fluidframework.

Yeah this is abit of a pain. You can always do:

type ICell = {
    text: JsonablePrimitive;
    cache: JsonablePrimitive;
}

or

interface ICell {
    text: JsonablePrimitive;
    cache: JsonablePrimitive;
    [other: string]: unknown
}

The latter is probably more honest unless you're explicitly filtering out properties before serialising.

Could also do:

private loadCell(row: number, col: number): ICell {
    return this.matrix.getItem(row, col) as Pick<ICell, keyof ICell>;
}

private storeCell(row: number, col: number, cell: Pick<ICell, keyof ICell>) {
    return this.matrix.setItems(row, col, [cell as Jsonable]);
}

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tagging myself for future developments on this issue

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Because this issue is marked as "won't fix" and has not had activity for over 3 days, we're automatically closing it for house-keeping purposes.

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