@fluidframework/datastore-definitions Package

This library defines the interfaces required to implement and/or communicate with a data store.

Interfaces

Interface	Alerts	Description
IChannel	`ALPHA`
IChannelAttributes	`ALPHA`	Represents the attributes of a channel/DDS.
IChannelFactory	`ALPHA`	Definitions of a channel factory.
IChannelServices	`ALPHA`	Storage services to read the objects at a given path using the given delta connection.
IChannelStorageService	`ALPHA`	Storage services to read the objects at a given path.
IDeltaConnection	`ALPHA`	Interface to represent a connection to a delta notification stream.
IDeltaHandler	`ALPHA`	Handler provided by shared data structure to process requests from the runtime.
IFluidDataStoreRuntime	`ALPHA`	Represents the runtime for the data store. Contains helper functions/state of the data store.
IFluidDataStoreRuntimeEvents	`ALPHA`	Events emitted by IFluidDataStoreRuntime.

Types

TypeAlias	Alerts	Description
Jsonable	`ALPHA`	Used to constrain a type `T` to types that are serializable as JSON. Produces a compile-time error if `T` contains non-Jsonable members.
Serializable	`ALPHA`	Used to constrain a type 'T' to types that Fluid can intrinsically serialize. Produces a compile-time error if `T` contains non-serializable members.

Type Details

Jsonable (ALPHA)

Used to constrain a type T to types that are serializable as JSON. Produces a compile-time error if T contains non-Jsonable members.

WARNING: This API is provided as an alpha preview and may change without notice. Use at your own risk.

Signature

export type Jsonable<T = any, TReplaced = void> = T extends undefined | null | boolean | number | string | TReplaced ? T : Extract<T, Function> extends never ? {
    [K in keyof T]: Extract<K, symbol> extends never ? Jsonable<T[K], TReplaced> : never;
} : never;

Remarks

Note that this does NOT prevent using of values with non-json compatible data, it only prevents using values with types that include non-json compatible data. This means that one can, for example, pass an a value typed with json compatible interface into this function, that could actually be a class with lots on non-json compatible fields and methods.

Important: T extends Jsonable<T> is incorrect (does not even compile). T extends Jsonable is also incorrect since Jsonable is just any and thus applies no constraint at all.

The optional ‘TReplaced’ parameter may be used to permit additional leaf types to support situations where a replacer is used to handle special values (e.g., Jsonable<{ x: IFluidHandle }, IFluidHandle>).

Note that Jsonable<T> does not protect against the following pitfalls when serializing with JSON.stringify():

undefined properties on objects are omitted (i.e., properties become undefined instead of equal to undefined).
When undefined appears as the root object or as an array element it is coerced to null.
Non-finite numbers (NaN, +/-Infinity) are also coerced to null.
prototypes and non-enumerable properties are lost.

Also, Jsonable<T> does not prevent the construction of circular references.

Using Jsonable (with no type parameters) or Jsonable<any> is just a type alias for any and should not be used if type safety is desired.

Example

Typical usage

function foo<T>(value: Jsonable<T>) { ... }

Serializable (ALPHA)

Used to constrain a type ‘T’ to types that Fluid can intrinsically serialize. Produces a compile-time error if T contains non-serializable members.

WARNING: This API is provided as an alpha preview and may change without notice. Use at your own risk.

Signature

export type Serializable<T = any> = Jsonable<T, IFluidHandle>;

Remarks

See Jsonable for caveats regarding serialization of undefined, non-finite numbers, and circular references.

Important: T extends Serializable<T> is generally incorrect. (Any value of T extends the serializable subset of itself.)

Example

Typical usage

function serialize<T>(value: Serializable<T>) { ... }