SchemaFactory Class

Packages > @fluidframework/tree > SchemaFactory

Creates various types of schema for TreeNode s.

Signature

/** @sealed */
export declare class SchemaFactory<out TScope extends string | undefined = string | undefined, TName extends number | string = string>

Type Parameters

Remarks

All schema produced by this factory get a unique identifier by combining the scope with the schema’s Name. The Name part may be explicitly provided as a parameter, or inferred as a structural combination of the provided types. The APIs which use this second approach, structural naming, also deduplicate all equivalent calls. Therefor two calls to array(allowedTypes) with the same allowedTypes will return the same TreeNodeSchema instance. On the other hand, two calls to array(name, allowedTypes) will always return different TreeNodeSchema instances and it is an error to use both in the same tree (since their identifiers are not unique).

Note: POJO stands for Plain Old JavaScript Object. This means an object that works like a {} style object literal. In this case it means the prototype is Object.prototype and acts like a set of key value pairs (data, not methods). The usage below generalizes this to include array and map like objects as well.

There are two ways to use these APIs:

Customizable Approach:

1. Declaration: class X extends schemaFactory.object("x", {}) {}

2. Allows adding “local” (non-persisted) members: Yes. Members (including methods) can be added to the class.

3. Prototype: The user-defined class.

4. Structurally named Schema: Not Supported.

5. Explicitly named Objects: Supported.

6. Explicitly named Maps and Arrays: Supported: Both declaration approaches can be used.

7. Node.js assert.deepEqual: Compares like class instances: equal to other nodes of the same type with the same content, including custom local fields.

8. IntelliSense: Shows and links to user-defined class by name: X.

9. Recursion: Supported with special declaration patterns.

POJO Emulation Approach:

1. Declaration: const X = schemaFactory.object("x", {}); type X = NodeFromSchema<typeof X>;

2. Allows adding “local” (non-persisted) members: No. Attempting to set non-field members will result in an error.

3. Prototype: Object.prototype, Map.prototype, or Array.prototype depending on node kind.

4. Structurally named Schema: Supported.

5. Explicitly named Objects: Supported.

6. Explicitly named Maps and Arrays: Not Supported.

7. Node.js assert.deepEqual: Compares like plain objects: equal to plain JavaScript objects with the same fields, and other nodes with the same fields, even if the types are different.

8. IntelliSense: Shows internal type generation logic: object & TreeNode & ObjectFromSchemaRecord<{}> & WithType<"test.x">.

9. Recursion: Unsupported: Generated .d.ts files replace recursive references with any, breaking the use of recursive schema across compilation boundaries.

Note that while “POJO Emulation” nodes act a lot like POJO objects, they are not true POJO objects:

• Adding new arbitrary fields will error, as well some cases of invalid edits.

• They are implemented using proxies.

• They have state that is not exposed via enumerable own properties, including a TreeNodeSchema . This makes libraries like node.js assert.deepEqual fail to detect differences in type.

• Assigning members has side effects (in this case editing the persisted/shared tree).

• Not all operations implied by the prototype will work correctly: stick to the APIs explicitly declared in the TypeScript types.

Constructors

Properties

Methods

Constructor Details

(constructor)

Construct a SchemaFactory with a given scope.

Signature

constructor(scope: TScope);

Remarks

There are no restrictions on mixing schema from different schema factories: this is encouraged when a single schema references schema from different libraries. If each library exporting schema picks its own globally unique scope for its SchemaFactory, then all schema an application might depend on, directly or transitively, will end up with a unique fully qualified name which is required to refer to it in persisted data and errors.

Parameters

Property Details

boolean

TreeNodeSchema for holding a boolean.

Signature

readonly boolean: TreeNodeSchema<"com.fluidframework.leaf.boolean", NodeKind.Leaf, boolean, boolean>;

Type: TreeNodeSchema <“com.fluidframework.leaf.boolean”, NodeKind.Leaf , boolean, boolean>

handle

TreeNodeSchema for holding an IFluidHandle .

Signature

readonly handle: TreeNodeSchema<"com.fluidframework.leaf.handle", NodeKind.Leaf, _dummyImport<unknown>, _dummyImport<unknown>>;

Type: TreeNodeSchema <“com.fluidframework.leaf.handle”, NodeKind.Leaf , _dummyImport <unknown>, _dummyImport <unknown>>

identifier

A special field which holds a unique identifier for an object node.

Signature

get identifier(): FieldSchema<FieldKind.Identifier, typeof this.string>;

Type: FieldSchema <FieldKind.Identifier , typeof this.string >

Remarks

The value of this field, a “node identifier”, uniquely identifies a node among all other nodes in the tree. Node identifiers are strings, and can therefore be used as lookup keys in maps or written to a database. When the node is constructed, the identifier field does not need to be populated. The SharedTree will provide an identifier for the node automatically. An identifier provided automatically by the SharedTree has the following properties: - It is a UUID. - It is compressed to a space-efficient representation when stored in the document. - A compressed form of the identifier can be accessed at runtime via the Tree.shortId() API. - It will error if read (and will not be present in the object’s iterable properties) before the node has been inserted into the tree.

However, a user may alternatively supply their own string as the identifier if desired (for example, if importing identifiers from another system). In that case, it is up to the user to ensure that the identifier is unique within the current tree - no other node should have the same identifier at the same time. If the identifier is not unique, it may be read, but may cause libraries or features which operate over node identifiers to misbehave. User-supplied identifiers may be read immediately, even before insertion into the tree.

A node may have more than one identifier field (though note that this precludes the use of the Tree.shortId() API).

null

TreeNodeSchema for JavaScript null.

Signature

readonly null: TreeNodeSchema<"com.fluidframework.leaf.null", NodeKind.Leaf, null, null>;

Type: TreeNodeSchema <“com.fluidframework.leaf.null”, NodeKind.Leaf , null, null>

Remarks

There are good [reasons to avoid using null](https://www.npmjs.com/package/%40rushstack/eslint-plugin #rushstackno-new-null) in JavaScript, however sometimes it is desired. This TreeNodeSchema node provides the option to include nulls in trees when desired. Unless directly inter-operating with existing data using null, consider other approaches, like wrapping the value in an optional field, or using a more specifically named empty object node.

number

TreeNodeSchema for holding a JavaScript number.

Signature

readonly number: TreeNodeSchema<"com.fluidframework.leaf.number", NodeKind.Leaf, number, number>;

Type: TreeNodeSchema <“com.fluidframework.leaf.number”, NodeKind.Leaf , number, number>

Remarks

The number is a [double-precision 64-bit binary format IEEE 754](https://en.wikipedia.org/wiki/Double-precision _floating-point_format) value, however there are some exceptions: - NaN, and the infinities are converted to null (and may therefore only be used where null is allowed by the schema). - -0 may be converted to 0 in some cases.

These limitations match the limitations of JSON.

scope

Signature

readonly scope: TScope;

Type: TScope

string

TreeNodeSchema for holding a JavaScript string.

Signature

readonly string: TreeNodeSchema<"com.fluidframework.leaf.string", NodeKind.Leaf, string, string>;

Type: TreeNodeSchema <“com.fluidframework.leaf.string”, NodeKind.Leaf , string, string>

Remarks

Strings containing unpaired UTF-16 surrogate pair code units may not be handled correctly.

These limitations come from the use of UTF-8 encoding of the strings, which requires them to be valid unicode. JavaScript does not make this requirement for its strings so not all possible JavaScript strings are supported.

Method Details

array

Define a structurally typed TreeNodeSchema for a TreeArrayNode .

Signature

array<const T extends TreeNodeSchema | readonly TreeNodeSchema[]>(allowedTypes: T): TreeNodeSchemaNonClass<ScopedSchemaName<TScope, `Array<${string}>`>, NodeKind.Array, TreeArrayNode<T> & WithType<ScopedSchemaName<TScope, `Array<${string}>`>, NodeKind.Array>, Iterable<InsertableTreeNodeFromImplicitAllowedTypes<T>>, true, T>;

Type Parameters

Remarks

The identifier for this Array is defined as a function of the provided types. It is still scoped to this SchemaFactory, but multiple calls with the same arguments will return the same schema object, providing somewhat structural typing. This does not support recursive types.

If using these structurally named arrays, other types in this schema builder should avoid names of the form Array<${string}>.

Example

The returned schema should be used as a schema directly:

const MyArray = factory.array(factory.number);
type MyArray = NodeFromSchema<typeof MyArray>;

Or inline:

factory.object("Foo", {myArray: factory.array(factory.number)});

Parameters

Returns

Return type: TreeNodeSchemaNonClass <ScopedSchemaName <TScope, `Array<${string}>`>, NodeKind.Array , TreeArrayNode <T> & WithType <ScopedSchemaName <TScope, `Array<${string}>`>, NodeKind.Array >, Iterable<InsertableTreeNodeFromImplicitAllowedTypes <T>>, true, T>

array

Define (and add to this library) a TreeNodeSchemaClass for a TreeArrayNode .

Signature

array<const Name extends TName, const T extends ImplicitAllowedTypes>(name: Name, allowedTypes: T): TreeNodeSchemaClass<ScopedSchemaName<TScope, Name>, NodeKind.Array, TreeArrayNode<T> & WithType<ScopedSchemaName<TScope, Name>, NodeKind.Array>, Iterable<InsertableTreeNodeFromImplicitAllowedTypes<T>>, true, T>;

Type Parameters

Example

class NamedArray extends factory.array("name", factory.number) {}

Parameters

Returns

Return type: TreeNodeSchemaClass <ScopedSchemaName <TScope, Name>, NodeKind.Array , TreeArrayNode <T> & WithType <ScopedSchemaName <TScope, Name>, NodeKind.Array >, Iterable<InsertableTreeNodeFromImplicitAllowedTypes <T>>, true, T>

arrayRecursive

SchemaFactory.array except tweaked to work better for recursive types. Use with ValidateRecursiveSchema for improved type safety.

Signature

arrayRecursive<const Name extends TName, const T extends Unenforced<ImplicitAllowedTypes>>(name: Name, allowedTypes: T): TreeNodeSchemaClass<ScopedSchemaName<TScope, Name>, NodeKind.Array, TreeArrayNodeUnsafe<T> & WithType<ScopedSchemaName<TScope, Name>, NodeKind.Array, unknown>, {
        [Symbol.iterator](): Iterator<InsertableTreeNodeFromImplicitAllowedTypesUnsafe<T>>;
    }, false, T>;

Type Parameters

Remarks

This version of SchemaFactory.array uses the same workarounds as objectRecursive(name, t) . See ValidateRecursiveSchema for additional information about using recursive schema.

Parameters

Returns

Return type: TreeNodeSchemaClass <ScopedSchemaName <TScope, Name>, NodeKind.Array , TreeArrayNodeUnsafe <T> & WithType <ScopedSchemaName <TScope, Name>, NodeKind.Array , unknown>, { [Symbol.iterator](): Iterator<InsertableTreeNodeFromImplicitAllowedTypesUnsafe <T>>; }, false, T>

map

Define a structurally typed TreeNodeSchema for a TreeMapNode .

Signature

map<const T extends TreeNodeSchema | readonly TreeNodeSchema[]>(allowedTypes: T): TreeNodeSchemaNonClass<ScopedSchemaName<TScope, `Map<${string}>`>, NodeKind.Map, TreeMapNode<T> & WithType<ScopedSchemaName<TScope, `Map<${string}>`>, NodeKind.Map>, MapNodeInsertableData<T>, true, T>;

Type Parameters

Remarks

The unique identifier for this Map is defined as a function of the provided types. It is still scoped to this SchemaBuilder, but multiple calls with the same arguments will return the same schema object, providing somewhat structural typing. This does not support recursive types.

If using these structurally named maps, other types in this schema builder should avoid names of the form Map<${string}>.

Example

The returned schema should be used as a schema directly:

const MyMap = factory.map(factory.number);
type MyMap = NodeFromSchema<typeof MyMap>;

Or inline:

factory.object("Foo", {myMap: factory.map(factory.number)});

Parameters

Returns

Return type: TreeNodeSchemaNonClass <ScopedSchemaName <TScope, `Map<${string}>`>, NodeKind.Map , TreeMapNode <T> & WithType <ScopedSchemaName <TScope, `Map<${string}>`>, NodeKind.Map >, MapNodeInsertableData <T>, true, T>

map

Define a TreeNodeSchema for a TreeMapNode .

Signature

map<Name extends TName, const T extends ImplicitAllowedTypes>(name: Name, allowedTypes: T): TreeNodeSchemaClass<ScopedSchemaName<TScope, Name>, NodeKind.Map, TreeMapNode<T> & WithType<ScopedSchemaName<TScope, Name>, NodeKind.Map>, MapNodeInsertableData<T>, true, T>;

Type Parameters

Example

class NamedMap extends factory.map("name", factory.number) {}

Parameters

Returns

Return type: TreeNodeSchemaClass <ScopedSchemaName <TScope, Name>, NodeKind.Map , TreeMapNode <T> & WithType <ScopedSchemaName <TScope, Name>, NodeKind.Map >, MapNodeInsertableData <T>, true, T>

mapRecursive

SchemaFactory.map except tweaked to work better for recursive types. Use with ValidateRecursiveSchema for improved type safety.

Signature

mapRecursive<Name extends TName, const T extends Unenforced<ImplicitAllowedTypes>>(name: Name, allowedTypes: T): TreeNodeSchemaClass<ScopedSchemaName<TScope, Name>, NodeKind.Map, TreeMapNodeUnsafe<T> & WithType<ScopedSchemaName<TScope, Name>, NodeKind.Map, unknown>, {
        [Symbol.iterator](): Iterator<[
            string,
            InsertableTreeNodeFromImplicitAllowedTypesUnsafe<T>
        ]>;
    }, false, T>;

Type Parameters

Remarks

This version of SchemaFactory.map uses the same workarounds as objectRecursive(name, t) . See ValidateRecursiveSchema for additional information about using recursive schema.

Parameters

Returns

Return type: TreeNodeSchemaClass <ScopedSchemaName <TScope, Name>, NodeKind.Map , TreeMapNodeUnsafe <T> & WithType <ScopedSchemaName <TScope, Name>, NodeKind.Map , unknown>, { [Symbol.iterator](): Iterator<[ string, InsertableTreeNodeFromImplicitAllowedTypesUnsafe <T> ]>; }, false, T>

object

Define a TreeNodeSchemaClass for a TreeObjectNode .

Signature

object<const Name extends TName, const T extends RestrictiveStringRecord<ImplicitFieldSchema>>(name: Name, fields: T): TreeNodeSchemaClass<ScopedSchemaName<TScope, Name>, NodeKind.Object, TreeObjectNode<T, ScopedSchemaName<TScope, Name>>, object & InsertableObjectFromSchemaRecord<T>, true, T>;

Type Parameters

Parameters

Returns

Return type: TreeNodeSchemaClass <ScopedSchemaName <TScope, Name>, NodeKind.Object , TreeObjectNode <T, ScopedSchemaName <TScope, Name>>, object & InsertableObjectFromSchemaRecord <T>, true, T>

objectRecursive

object(name, fields) except tweaked to work better for recursive types. Use with ValidateRecursiveSchema for improved type safety.

Signature

objectRecursive<const Name extends TName, const T extends Unenforced<RestrictiveStringRecord<ImplicitFieldSchema>>>(name: Name, t: T): TreeNodeSchemaClass<ScopedSchemaName<TScope, Name>, NodeKind.Object, TreeObjectNodeUnsafe<T, ScopedSchemaName<TScope, Name>>, object & { readonly [Property in keyof T as FieldHasDefaultUnsafe<T[Property]> extends false ? Property : never]: InsertableTreeFieldFromImplicitFieldUnsafe<T[Property]>; } & { readonly [Property_1 in keyof T as FieldHasDefaultUnsafe<T[Property_1]> extends true ? Property_1 : never]?: InsertableTreeFieldFromImplicitFieldUnsafe<T[Property_1]> | undefined; }, false, T>;

Type Parameters

Remarks

This version of object(name, fields) has fewer type constraints to work around TypeScript limitations, see Unenforced . See ValidateRecursiveSchema for additional information about using recursive schema.

Additionally ImplicitlyConstructable is disabled (forcing use of constructor) to avoid error TS2589: Type instantiation is excessively deep and possibly infinite. which otherwise gets reported at sometimes incorrect source locations that vary based on incremental builds.

Parameters

Returns

Return type: TreeNodeSchemaClass <ScopedSchemaName <TScope, Name>, NodeKind.Object , TreeObjectNodeUnsafe <T, ScopedSchemaName <TScope, Name>>, object & { readonly [Property in keyof T as FieldHasDefaultUnsafe <T[Property]> extends false ? Property : never]: InsertableTreeFieldFromImplicitFieldUnsafe <T[Property]>; } & { readonly [Property_1 in keyof T as FieldHasDefaultUnsafe <T[Property_1]> extends true ? Property_1 : never]?: InsertableTreeFieldFromImplicitFieldUnsafe <T[Property_1]> | undefined; }, false, T>

optional

Make a field optional instead of the default, which is required.

Signature

optional<const T extends ImplicitAllowedTypes, const TCustomMetadata = unknown>(t: T, props?: Omit<FieldProps<TCustomMetadata>, "defaultProvider">): FieldSchema<FieldKind.Optional, T, TCustomMetadata>;

Type Parameters

Parameters

Returns

Return type: FieldSchema <FieldKind.Optional , T, TCustomMetadata>

optionalRecursive

optional(t, props) except tweaked to work better for recursive types. Use with ValidateRecursiveSchema for improved type safety.

Signature

optionalRecursive<const T extends Unenforced<ImplicitAllowedTypes>>(t: T, props?: Omit<FieldProps, "defaultProvider">): FieldSchemaUnsafe<FieldKind.Optional, T>;

Type Parameters

Remarks

This version of optional(t, props) has fewer type constraints to work around TypeScript limitations, see Unenforced . See ValidateRecursiveSchema for additional information about using recursive schema.

Parameters

Returns

Return type: FieldSchemaUnsafe <FieldKind.Optional , T>

required

Make a field explicitly required.

Signature

required<const T extends ImplicitAllowedTypes, const TCustomMetadata = unknown>(t: T, props?: Omit<FieldProps<TCustomMetadata>, "defaultProvider">): FieldSchema<FieldKind.Required, T, TCustomMetadata>;

Type Parameters

Remarks

Fields are required by default, but this API can be used to make the required nature explicit in the schema, and allows associating custom properties with the field.

Parameters

Returns

Return type: FieldSchema <FieldKind.Required , T, TCustomMetadata>

requiredRecursive

required(t, props) except tweaked to work better for recursive types. Use with ValidateRecursiveSchema for improved type safety.

Signature

requiredRecursive<const T extends Unenforced<ImplicitAllowedTypes>>(t: T, props?: Omit<FieldProps, "defaultProvider">): FieldSchemaUnsafe<FieldKind.Required, T>;

Type Parameters

Remarks

This version of required(t, props) has fewer type constraints to work around TypeScript limitations, see Unenforced . See ValidateRecursiveSchema for additional information about using recursive schema.

Parameters

Returns

Return type: FieldSchemaUnsafe <FieldKind.Required , T>