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Documentation / @ember-data/model / migration-support / DelegatingSchemaService

Defined in: packages/model/src/migration-support.ts:388

The SchemaService provides the ability to query for information about the structure of any resource type.

Applications can provide any implementation of the SchemaService they please so long as it conforms to this interface.

The design of the service means that schema information could be lazily populated, derived-on-demand, or progressively enhanced during the course of an application's runtime. The primary requirement is merely that any information the service needs to correctly respond to an inquest is available by the time it is asked.

The @ember-data/model package provides an implementation of this service which makes use of your model classes as the source of information to respond to queries about resource schema. While this is useful, this may not be ideal for your application. For instance, Schema information could be sideloaded or pre-flighted for API calls, resulting in no need to bundle and ship potentially large and expensive JSON or large Javascript based Models to pull information from.

To register a custom schema implementation, implement the store's createSchemaService hook to return an instance of your service.

ts
import Store from '@ember-data/store';
import CustomSchemas from './custom-schemas';

export default class extends Store {
  createSchemaService() {
    return new CustomSchemas();
  }
}

At runtime, both the Store and the CacheCapabilitiesManager provide access to this service via the schema property.

ts
export default class extends Component {
 @service store;

 get fields() {
   return this.store
     .schema
     .fields(this.args.dataType);
 }
}

(Interface) SchemaService

Implements ​

Constructors ​

Constructor ​

ts
new DelegatingSchemaService(store, schema): DelegatingSchemaService;

Defined in: packages/model/src/migration-support.ts:397

Parameters ​

store ​

default

schema ​

SchemaService

Returns ​

DelegatingSchemaService

Properties ​

_preferred ​

ts
_preferred: SchemaService;

Defined in: packages/model/src/migration-support.ts:394

_secondary ​

ts
_secondary: SchemaService;

Defined in: packages/model/src/migration-support.ts:395

Methods ​

attributesDefinitionFor()? ​

ts
optional attributesDefinitionFor(resource): AttributesSchema;

Defined in: packages/model/src/migration-support.ts:389

DEPRECATED - use fields instead

Returns definitions for all properties of the specified resource that are considered "attributes". Generally these are properties that are not related to book-keeping state on the client and do not represent a linkage to another resource.

The return value should be a dictionary of key:value pairs where the key is the attribute or property's name and value is an object with at least the property name which should also match key.

Optionally, this object may also specify type, which should be a string reference to a transform, and options which should be dictionary in which any key:value pairs are permissable.

For instance, when using @ember-data/model, the following attribute definition:

ts
class extends Model {
  @attr('string', { defaultValue: 'hello' }) greeting;
  @attr('date') birthday;
  @attr firstName;
}

Would be returned as:

js
{
  greeting: { name: 'greeting', type: 'string', options: { defaultValue: 'hello' } },
  birthday: { name: 'birthday', type: 'date' },
  firstName: { name: 'firstName' }
}

Parameters ​

resource ​

StableRecordIdentifier | { type: string; }

Returns ​

AttributesSchema

Deprecated ​

derivation() ​

ts
derivation(field): Derivation;

Defined in: packages/model/src/migration-support.ts:437

Returns the derivation registered with the name provided by field.type. Validates that the field is a valid DerivedField.

Parameters ​

field ​

DerivedField | { type: string; }

Returns ​

Derivation

doesTypeExist()? ​

ts
optional doesTypeExist(type): boolean;

Defined in: packages/model/src/migration-support.ts:391

DEPRECATED - use hasResource instead

Queries whether the SchemaService recognizes type as a resource type

Parameters ​

type ​

string

Returns ​

boolean

Deprecated ​

fields() ​

ts
fields(resource): Map<string, FieldSchema>;

Defined in: packages/model/src/migration-support.ts:425

Queries for the fields of a given resource type or resource identity.

Should error if the resource type is not recognized.

Parameters ​

resource ​

StableRecordIdentifier | { type: string; }

Returns ​

Map<string, FieldSchema>

hashFn() ​

ts
hashFn(field): HashFn;

Defined in: packages/model/src/migration-support.ts:434

Returns the hash function registered with the name provided by field.type. Validates that the field is a valid HashField.

Parameters ​

field ​

HashField | { type: string; }

Returns ​

HashFn

hasResource() ​

ts
hasResource(resource): boolean;

Defined in: packages/model/src/migration-support.ts:410

Queries whether the SchemaService recognizes type as a resource type

Parameters ​

resource ​

StableRecordIdentifier | { type: string; }

Returns ​

boolean

hasTrait() ​

ts
hasTrait(type): boolean;

Defined in: packages/model/src/migration-support.ts:413

Queries whether the SchemaService recognizes type as a resource trait

Parameters ​

type ​

string

Returns ​

boolean

isDelegated() ​

ts
isDelegated(resource): boolean;

Defined in: packages/model/src/migration-support.ts:402

Parameters ​

resource ​

StableRecordIdentifier | { type: string; }

Returns ​

boolean

registerDerivation() ​

ts
registerDerivation<R, T, FM>(derivation): void;

Defined in: packages/model/src/migration-support.ts:455

Enables registration of a derivation.

The derivation can later be retrieved by the name attached to it's [Type] property.

Type Parameters ​

R ​

R

T ​

T

FM ​

FM extends | null | ObjectValue

Parameters ​

derivation ​

Derivation<R, T, FM>

Returns ​

void

registerHashFn() ​

ts
registerHashFn(hashFn): void;

Defined in: packages/model/src/migration-support.ts:458

Enables registration of a hashing function

The hashing function can later be retrieved by the name attached to it's [Type] property.

Parameters ​

hashFn ​

HashFn

Returns ​

void

registerResource() ​

ts
registerResource(schema): void;

Defined in: packages/model/src/migration-support.ts:449

Enables registration of a single Schema representing either a resource in PolarisMode or LegacyMode or an ObjectSchema representing an embedded structure in other schemas.

This can be useful for either pre-loading schema information or for registering schema information delivered by API calls or other sources just-in-time.

Parameters ​

schema ​

ResourceSchema | ObjectSchema

Returns ​

void

registerResources() ​

ts
registerResources(schemas): void;

Defined in: packages/model/src/migration-support.ts:446

Enables registration of multiple Schemas at once.

This can be useful for either pre-loading schema information or for registering schema information delivered by API calls or other sources just-in-time.

Parameters ​

schemas ​

( | ResourceSchema | ObjectSchema)[]

Returns ​

void

registerTransformation() ​

ts
registerTransformation(transform): void;

Defined in: packages/model/src/migration-support.ts:452

Enables registration of a transformation.

The transformation can later be retrieved by the name attached to it's [Type] property.

Parameters ​

transform ​

Transformation

Returns ​

void

relationshipsDefinitionFor()? ​

ts
optional relationshipsDefinitionFor(resource): RelationshipsSchema;

Defined in: packages/model/src/migration-support.ts:390

DEPRECATED - use fields instead

Returns definitions for all properties of the specified resource that are considered "relationships". Generally these are properties that represent a linkage to another resource.

The return value should be a dictionary of key:value pairs where the key is the relationship or property's name and value is an object with at least the following properties:

  • name which should also match the key used in the dictionary.

  • kind which should be either belongsTo or hasMany

  • type which should be the related resource's string "type"

  • options which should be a dictionary allowing any key but with at least the below keys present.

  • options.async a boolean representing whether data for this relationship is typically loaded on-demand.

  • options.inverse a string or null representing the field name / key of the corresponding relationship on the inverse resource.

Additionally the following options properties are optional. See Polymorphic Relationships

  • options.polymorphic a boolean representing whether multiple resource types can be used to satisfy this relationship.
  • options.as a string representing the abstract type that the concrete side of a relationship must specify when fulfilling a polymorphic inverse.

For example, the following Model using @ember-data/model would generate this relationships definition by default:

js
class User extends Model {
  @belongsTo('user', { async: false, inverse: null }) bestFriend;
  @hasMany('user', { async: true, inverse: 'friends' }) friends;
  @hasMany('pet', { async: false, polymorphic: true, inverse: 'owner' }) pets;
}

Which would be returned as

js
{
  bestFriend: {
    name: 'bestFriend',
    kind: 'belongsTo',
    type: 'user',
    options: {
      async: false,
      inverse: null
    }
  },
  friends: {
    name: 'friends',
    kind: 'hasMany',
    type: 'user',
    options: {
      async: true,
      inverse: 'friends'
    }
  },
  pets: {
    name: 'pets',
    kind: 'hasMany',
    type: 'pet',
    options: {
      async: false,
      polymorphic: true,
      inverse: 'owner'
    }
  },
}

Parameters ​

resource ​

StableRecordIdentifier | { type: string; }

Returns ​

RelationshipsSchema

Deprecated ​

resource() ​

ts
resource(resource): 
  | ResourceSchema
  | ObjectSchema;

Defined in: packages/model/src/migration-support.ts:440

Returns the schema for the provided resource type.

Parameters ​

resource ​

StableRecordIdentifier | { type: string; }

Returns ​

| ResourceSchema | ObjectSchema

resourceHasTrait() ​

ts
resourceHasTrait(resource, trait): boolean;

Defined in: packages/model/src/migration-support.ts:419

Queries whether the given resource has the given trait

Parameters ​

resource ​

StableRecordIdentifier | { type: string; }

trait ​

string

Returns ​

boolean

resourceTypes() ​

ts
resourceTypes(): readonly string[];

Defined in: packages/model/src/migration-support.ts:406

Returns all known resource types

Returns ​

readonly string[]

transformation() ​

ts
transformation(field): Transformation;

Defined in: packages/model/src/migration-support.ts:431

Returns the transformation registered with the name provided by field.type. Validates that the field is a valid transformable.

Parameters ​

field ​

GenericField | ObjectField | ArrayField | { type: string; }

Returns ​

Transformation

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