Realm

A Realm instance represents a Realm database.

const Realm = require('realm');

Related Classes

Collection
List
Object
Results
Sync
Worker
empty
readonly

Indicates if this Realm contains any objects.

Type:
boolean
isClosed
readonly

Indicates if this Realm has been closed.

Type:
boolean
isInTransaction
readonly

Indicates if this Realm is in a write transaction.

Type:
boolean
path
readonly

The path to the file where this Realm is stored.

Type:
string
readOnly
readonly

Indicates if this Realm was opened as read-only.

Type:
boolean
schema
readonly

A normalized representation of the schema provided in the Configuration when this Realm was constructed.

Type:
[ObjectSchema, ...]
schemaVersion
readonly

The current schema version of this Realm.

Type:
number
syncSession

Gets the sync session if this is a synced Realm

Type:
Session
new Realm(config)

Create a new Realm instance using the provided config. If a Realm does not yet exist at config.path (or Realm.defaultPath if not provided), then this constructor will create it with the provided config.schema (which is required in this case). Otherwise, the instance will access the existing Realm from the file at that path. In this case, config.schema is optional or not have changed, unless config.schemaVersion is incremented, in which case the Realm will be automatically migrated to use the new schema.

Parameters:
  • config optional
Realm.automaticSyncConfiguration(user)Configuration
staticDeprecated: use Sync.User.createConfiguration() instead.

Return a configuration for a default synced Realm. The server URL for the user will be used as base for the URL for the synced Realm. If no user is supplied, the current user will be used.

Parameters:
Throws:
  • Error
    • if zero or multiple users are logged in

Returns: Configuration
  • a configuration matching a default synced Realm.
Realm.createTemplateObject(schema)
static

Creates a template object for a Realm model class where all optional fields are undefined and all required fields have the default value for the given data type, either the value set by the default property in the schema or the default value for the datatype if the schema doesn't specify one, i.e. 0, false and "".

Parameters:
Realm.deleteFile(config)
static

Delete the Realm file for the given configuration.

Parameters:
Throws:
  • Error
    • If anything in the provided config is invalid.

Realm.open(config)ProgressPromise
static

Open a Realm asynchronously with a promise. If the Realm is synced, it will be fully synchronized before it is available.

Parameters:
  • config
    • Type: Configuration
    • if no config is defined, it will open the default realm

Returns: ProgressPromise
  • a promise that will be resolved with the Realm instance when it's available.
Realm.openAsync(config, callback, progressCallback)
static

Open a Realm asynchronously with a callback. If the Realm is synced, it will be fully synchronized before it is available.

Parameters:
  • callback
    • Type: callback(error, realm)
    • will be called when the Realm is ready.

  • progressCallback optional
    • Type: callback(transferred, transferable)
    • an optional callback for download progress notifications

Throws:
  • Error
    • If anything in the provided config is invalid

  • IncompatibleSyncedRealmError
    • when an incompatible synced Realm is opened

Realm.schemaVersion(path, encryptionKey)number
static

Get the current schema version of the Realm at the given path.

Parameters:
  • path
    • Type: string
    • The path to the file where the Realm database is stored.

  • encryptionKey optional
    • Type: ArrayBuffer or ArrayBufferView
    • Required only when accessing encrypted Realms.

Throws:
  • Error
    • When passing an invalid or non-matching encryption key.

Returns: number version of the schema, or -1 if no Realm exists at path.
addListener(name, callback)

Add a listener callback for the specified event name.

Parameters:
  • name
    • Type: string
    • The name of event that should cause the callback to be called. Currently, only the "change" and "schema" events are supported.

  • callback
    • Type: callback(Realm, string) or callback(Realm, string, Schema)
    • Function to be called when a change event occurs. Each callback will only be called once per event, regardless of the number of times it was added.

Throws:
  • Error
    • If an invalid event name is supplied, or if callback is not a function.

beginTransaction()

Initiate a write transaction.

Throws:
  • Error
    • When already in write transaction

cancelTransaction()

Cancel a write transaction.

close()

Closes this Realm so it may be re-opened with a newer schema version. All objects and collections from this Realm are no longer valid after calling this method.

commitTransaction()

Commit a write transaction.

compact()true

Replaces all string columns in this Realm with a string enumeration column and compacts the database file.

Cannot be called from a write transaction.

Compaction will not occur if other Realm instances exist.

While compaction is in progress, attempts by other threads or processes to open the database will wait.

Be warned that resource requirements for compaction is proportional to the amount of live data in the database. Compaction works by writing the database contents to a temporary database file and then replacing the database with the temporary one.

Returns: true if compaction succeeds.
create(type, properties, update)Realm.Object

Create a new Realm object of the given type and with the specified properties.

Parameters:
  • type
    • Type: ObjectType
    • The type of Realm object to create.

  • properties
    • Type: Object
    • Property values for all required properties without a default value.

  • update optional
    • Type: boolean
    • Default: false
    • Signals that an existing object with matching primary key should be updated. Only the primary key property and properties which should be updated need to be specified. All missing property values will remain unchanged.

Returns: Realm.Object
delete(object)

Deletes the provided Realm object, or each one inside the provided collection.

Parameters:
deleteAll()

WARNING: This will delete all objects in the Realm!

deleteModel(name)

Deletes a Realm model, including all of its objects.

Parameters:
  • name
    • Type: string
    • the model name

objectForPrimaryKey(type, key)Realm.Object or undefined

Searches for a Realm object by its primary key.

Parameters:
  • type
    • Type: ObjectType
    • The type of Realm object to search for.

  • key
    • Type: number or string
    • The primary key value of the object to search for.

Throws:
  • Error
    • If type passed into this method is invalid or if the object type did not have a primaryKey specified in its ObjectSchema.

Returns: Realm.Object or undefined if no object is found.
objects(type)Realm.Results

Returns all objects of the given type in the Realm.

Parameters:
  • type
    • Type: ObjectType
    • The type of Realm objects to retrieve.

Throws:
  • Error
    • If type passed into this method is invalid.

Returns: Realm.Results that will live-update as objects are created and destroyed.
privileges(arg)Object

Returns the granted privilges.

This combines all privileges granted on the Realm/Class/Object by all Roles which the current User is a member of into the final privileges which will be enforced by the server.

The privilege calculation is done locally using cached data, and inherently may be stale. It is possible that this method may indicate that an operation is permitted but the server will still reject it if permission is revoked before the changes have been integrated on the server.

Non-synchronized Realms always have permission to perform all operations.

See: {Realm.Permissions} for details of priviliges and roles.
Parameters:
Returns: Object as the computed priviliges as properties
removeAllListeners(name)

Remove all event listeners (restricted to the event name, if provided).

Parameters:
  • name optional
    • Type: string
    • The name of the event whose listeners should be removed. Currently, only the "change" and "schema" events are supported.

Throws:
  • Error
    • When invalid event name is supplied

removeListener(name, callback)

Remove the listener callback for the specfied event name.

Parameters:
  • name
    • Type: string
    • The event name. Currently, only the "change" and "schema" events are supported.

  • callback
    • Type: callback(Realm, string) or callback(Realm, string, Schema)
    • Function that was previously added as a listener for this event through the addListener method.

Throws:
  • Error
    • If an invalid event name is supplied, or if callback is not a function.

write(callback)

Synchronously call the provided callback inside a write transaction.

Parameters:
  • callback
    • Type: function
writeCopyTo(path, encryptionKey)

Writes a compacted copy of the Realm to the given path.

The destination file cannot already exist.

Note that if this method is called from within a write transaction, the current data is written, not the data from the point when the previous write transaction was committed.

Parameters:
  • path
    • Type: string
    • path to save the Realm to

  • encryptionKey optional
    • Type: ArrayBuffer or ArrayBufferView
    • Optional 64-byte encryption key to encrypt the new file with.

Configuration

This describes the different options used to create a Realm instance.

Type:
Object
Properties:
  • encryptionKey optional
    • Type: ArrayBuffer or ArrayBufferView
    • The 512-bit (64-byte) encryption key used to encrypt and decrypt all data in the Realm.

  • migration optional
    • Type: callback(Realm, Realm)
    • The function to run if a migration is needed. This function should provide all the logic for converting data models from previous schemas to the new schema. This function takes two arguments:

      • oldRealm - The Realm before migration is performed.
      • newRealm - The Realm that uses the latest schema, which should be modified as necessary.
  • deleteRealmIfMigrationNeeded optional
    • Type: boolean
    • Default: false
    • Specifies if this Realm should be deleted if a migration is needed.

  • shouldCompactOnLaunch optional
    • Type: callback(number, number)
    • The function called when opening a Realm for the first time during the life of a process to determine if it should be compacted before being returned to the user. The function takes two arguments:

      - `totalSize` - The total file size (data + free space)
      - `usedSize` - The total bytes used by data in the file.

      It returns true to indicate that an attempt to compact the file should be made. The compaction will be skipped if another process is accessing it.

  • path optional
    • Type: string
    • Default: Realm.defaultPath
    • The path to the file where the Realm database should be stored.

  • inMemory optional
    • Type: boolean
    • Default: false
    • Specifies if this Realm should be opened in-memory. This still requires a path (can be the default path) to identify the Realm so other processes can open the same Realm. The file will also be used as swap space if the Realm becomes bigger than what fits in memory, but it is not persistent and will be removed when the last instance is closed.

  • readOnly optional
    • Type: boolean
    • Default: false
    • Specifies if this Realm should be opened as read-only.

  • disableFormatUpgrade optional
    • Type: boolean
    • Default: false
    • Specifies if this Realm's file format should be automatically upgraded if it was created with an older version of the Realm library. If set to true and a file format upgrade is required, an error will be thrown instead.

  • schema optional
    • Type: [(ObjectClass | ObjectSchema), ...]
    • Specifies all the object types in this Realm. Required when first creating a Realm at this path. If omitted, the schema will be read from the existing Realm file.

  • schemaVersion optional
    • Type: number
    • Required (and must be incremented) after changing the schema.

ObjectClass

Realm objects will inherit methods, getters, and setters from the prototype of this constructor. It is highly recommended that this constructor inherit from Realm.Object.

Type:
Class
Properties:
  • schema
    • Type: ObjectSchema
    • Static property specifying object schema information.

ObjectSchema
Type:
Object
Properties:
  • name
    • Type: string
    • Represents the object type.

  • primaryKey optional
    • Type: string
    • The name of a "string" or "int" property that must be unique across all objects of this type within the same Realm.

  • properties
Example:
let MyClassSchema = {
    name: 'MyClass',
    primaryKey: 'pk',
    properties: {
        pk: 'int',
        optionalFloatValue: 'float?' // or {type: 'float', optional: true}
        listOfStrings: 'string[]',
        listOfOptionalDates: 'date?[]',
        indexedInt: {type: 'int', indexed: true}

        linkToObject: 'MyClass',
        listOfObjects: 'MyClass[]', // or {type: 'list', objectType: 'MyClass'}
        objectsLinkingToThisObject: {type: 'linkingObjects', objectType: 'MyClass', property: 'linkToObject'}
    }
};
ObjectSchemaProperty
Type:
Object
Properties:
  • objectType optional
    • Type: PropertyType
    • Required when type is "list" or "linkingObjects", and must match the type of an object in the same schema, or, for "list" only, any other type which may be stored as a Realm property.

  • property optional
    • Type: string
    • Required when type is "linkingObjects", and must match the name of a property on the type specified in objectType that links to the type this property belongs to.

  • default optional
    • Type: any
    • The default value for this property on creation when not otherwise specified.

  • optional optional
    • Type: boolean
    • Signals if this property may be assigned null or undefined. For "list" properties of non-object types, this instead signals whether the values inside the list may be assigned null or undefined. This is not supported for "list" properties of object types and "linkingObjects" properties.

  • indexed optional
    • Type: boolean
    • Signals if this property should be indexed. Only supported for "string", "int", and "bool" properties.

ObjectType

The type of an object may either be specified as a string equal to the name in a ObjectSchema definition, or a constructor that was specified in the configuration schema.

Type:
string or ObjectClass
PropertyType

A property type may be specified as one of the standard builtin types, or as an object type inside the same schema.

When specifying property types in an object schema, you may append ? to any of the property types to indicate that it is optional (i.e. it can be null in addition to the normal values) and [] to indicate that it is instead a list of that type. For example, optionalIntList: 'int?[]' would declare a property which is a list of nullable integers. The property types reported by collections and in a Realm's schema will never use these forms.

Type:
"bool" or "int" or "float" or "double" or "string" or "date" or "data" or "list" or "linkingObjects" or "<ObjectType>"
Properties:
  • "bool"
    • Type: boolean
    • Property value may either be true or false.

  • "int"
    • Type: number
    • Property may be assigned any number, but will be stored as a round integer, meaning anything after the decimal will be truncated.

  • "float"
    • Type: number
    • Property may be assigned any number, but will be stored as a float, which may result in a loss of precision.

  • "double"
    • Type: number
    • Property may be assigned any number, and will have no loss of precision.

  • "string"
    • Type: string
    • Property value may be any arbitrary string.

  • "date"
    • Type: Date
    • Property may be assigned any Date instance.

  • "data"
    • Type: ArrayBuffer
    • Property may either be assigned an ArrayBuffer or ArrayBufferView (e.g. DataView, Int8Array, Float32Array, etc.) instance, but will always be returned as an ArrayBuffer.

  • "linkingObjects"
  • "<ObjectType>"
    • Type: Realm.Object
    • A string that matches the name of an object in the same schema (see ObjectSchema) – this property may be assigned any object of this type from inside the same Realm, and will always be optional (meaning it may also be assigned null or undefined).