js-data

Class: Collection

Collection

new Collection(records, opts)

An ordered set of Record instances.

Method parameters:
Name Type Argument Description
records Array <optional>

Initial set of records to insert into the collection.
opts Object <optional>

Configuration options.

Properties
Name Type Argument Default Description
idAttribute String <optional>

See Collection#idAttribute.
onConflict String <optional>
 "merge"

See Collection#onConflict.
mapper String <optional>

See Collection#mapper.
Details
Type Source
Function Collection.js, line 46
Example 
import {Collection, Record} from 'js-data'
const user1 = new Record({ id: 1 })
const user2 = new Record({ id: 2 })
const UserCollection = new Collection([user1, user2])
UserCollection.get(1) === user1 // true

Extends

This class extends the Component class.

Members

_listeners

Event listeners attached to this Component. Do not modify. Use Component#on and Component#off instead.

Details
Type Since Source
Object 3.0.0 Component.js, line 7
Inherited From:

idAttribute

Field to be used as the unique identifier for records in this collection. Defaults to "id" unless Collection#mapper is set, in which case this will default to Mapper#idAttribute.

Details
Type Default value Source
String 
"id"
 Collection.js, line 9

index

The main index, which uses @{link Collection#recordId} as the key.

Details
Type Source
Index Collection.js, line 125

indexes

Object that holds the secondary indexes of this collection.

Details
Type Source
Object.<string, Index> Collection.js, line 139

mapper

Default Mapper for this collection. Optional. If a Mapper is provided, then the collection will use the Mapper#idAttribute setting, and will wrap records in Mapper#recordClass.

Details
Type Default value Source
Mapper 
null
 Collection.js, line 83
Example 
import {Collection, Mapper} from 'js-data'

class MyMapperClass extends Mapper {
  foo () { return 'bar' }
}
const myMapper = new MyMapperClass()
const collection = new Collection(null, { mapper: myMapper })

onConflict

What to do when inserting a record into this Collection that shares a primary key with a record already in this Collection.

Possible values:

  • merge
  • replace

Merge:

Recursively shallow copy properties from the new record onto the existing record.

Replace:

Shallow copy top-level properties from the new record onto the existing record. Any top-level own properties of the existing record that are not on the new record will be removed.

Details
Type Default value Source
String 
"merge"
 Collection.js, line 20

Methods

add(data, opts)

Insert the provided record or records.

If a record is already in the collection then the provided record will either merge with or replace the existing record based on the value of the onConflict option.

The collection's secondary indexes will be updated as each record is visited.

Method parameters:
Name Type Argument Description
data Object | Array.<Object> | Record | Array.<Record>

The record or records to insert.
opts Object <optional>

Configuration options.

Properties
Name Type Argument Description
onConflict String <optional>

What to do when a record is already in the collection. Possible values are merge or replace.
Return value:
Type Description
Object | Array.<Object> | Record | Array.<Record>

The added record or records.
Details
Since Source
3.0.0 Collection.js, line 168

afterRemove(id, opts, record)

Lifecycle hook called by Collection#remove. If this method returns a value then Collection#remove will return that same value.

Method parameters:
Name Type Description
id String | Number

The id argument passed to Collection#remove.
opts Object

The opts argument passed to Collection#remove.
record Object

The result that will be returned by Collection#remove.
Details
Since Source
3.0.0 Collection.js, line 276

afterRemoveAll(query, opts, records)

Lifecycle hook called by Collection#removeAll. If this method returns a value then Collection#removeAll will return that same value.

Method parameters:
Name Type Description
query Object

The query argument passed to Collection#removeAll.
opts Object

The opts argument passed to Collection#removeAll.
records Object

The result that will be returned by Collection#removeAll.
Details
Since Source
3.0.0 Collection.js, line 288

beforeAdd(records, opts)

Lifecycle hook called by Collection#add. If this method returns a value then the records argument in Collection#add will be re-assigned to the returned value.

Method parameters:
Name Type Description
records Object | Array.<Object> | Record | Array.<Record>

The records argument passed to Collection#add.
opts Object

The opts argument passed to Collection#add.
Details
Since Source
3.0.0 Collection.js, line 301

beforeRemove(id, opts)

Lifecycle hook called by Collection#remove.

Method parameters:
Name Type Description
id String | Number

The id argument passed to Collection#remove.
opts Object

The opts argument passed to Collection#remove.
Details
Since Source
3.0.0 Collection.js, line 313

beforeRemoveAll(query, opts)

Lifecycle hook called by Collection#removeAll.

Method parameters:
Name Type Description
query Object

The query argument passed to Collection#removeAll.
opts Object

The opts argument passed to Collection#removeAll.
Details
Since Source
3.0.0 Collection.js, line 323

between(leftKeys, rightKeys, opts)

Find all records between two boundaries.

Shortcut for collection.query().between(18, 30, { index: 'age' }).run()

Method parameters:
Name Type Argument Description
leftKeys Array

Keys defining the left boundary.
rightKeys Array

Keys defining the right boundary.
opts Object <optional>

Configuration options.

Properties
Name Type Argument Default Description
index String <optional>

Name of the secondary index to use in the query. If no index is specified, the main index is used.
leftInclusive Boolean <optional>
 true

Whether to include records on the left boundary.
rightInclusive Boolean <optional>
 false

Whether to include records on the left boundary.
limit Boolean <optional>

Limit the result to a certain number.
offset Boolean <optional>

The number of resulting records to skip.
Return value:
Type Description
Array

The result.
Details
Since Source
3.0.0 Collection.js, line 333
Examples

Get all users ages 18 to 30

const users = collection.between(18, 30, { index: 'age' })

Same as above

const users = collection.between([18], [30], { index: 'age' })

createIndex(name, fieldList)

Create a new secondary index on the contents of the collection.

Method parameters:
Name Type Argument Description
name String

The name of the new secondary index.
fieldList Array.<String> <optional>

Array of field names to use as the key or compound key of the new secondary index. If no fieldList is provided, then the name will also be the field that is used to index the collection.
Return value:
Type Description
Collection

A reference to itself for chaining.
Details
Since Source
3.0.0 Collection.js, line 363
Examples

Index users by age

collection.createIndex('age')

Index users by status and role

collection.createIndex('statusAndRole', ['status', 'role'])

dbg(args)

Log the provided values at the "debug" level.

Method parameters:
Name Type Argument Description
args * <optional>
<repeatable>

Values to log.
Details
Since Source
3.0.0 Component.js, line 32
Inherited From:

emit(event, args)

Trigger an event on this Component.

Method parameters:
Name Type Argument Description
event String

Name of event to emit.
args * <optional>
<repeatable>

Arguments to pass to any listeners.
Details
Since Source
3.0.0 Component.js, line 98
Inherited From:
Examples 
collection.on('foo', (msg) => {
  console.log(msg) // "bar"
})
collection.emit('foo', 'bar')
store.on('foo', (msg, val1, val2) => {
  console.log(msg, val1, val2) // "bar" "beep" "boop"
})
store.emit('foo', 'bar', 'beep', 'boop')

filter(queryOrFn, thisArg)

Find the record or records that match the provided query or pass the provided filter function.

Shortcut for collection.query().filter(queryOrFn[, thisArg]).run()

Method parameters:
Name Type Argument Default Description
queryOrFn Object | Function <optional>
 {}

Selection query or filter function.
thisArg Object <optional>

Context to which to bind queryOrFn if queryOrFn is a function.
Return value:
Type Description
Array

The result.
Details
Since Source
3.0.0 Collection.js, line 391
Examples

Get the draft posts created less than three months

const posts = collection.filter({
  where: {
    status: {
      '==': 'draft'
    },
    created_at_timestamp: {
      '>=': (new Date().getTime() - (1000 * 60 * 60 * 24 * 30 * 3)) // 3 months ago
    }
  }
})

Use a custom filter function

const posts = collection.filter(function (post) {
  return post.isReady()
})

forEach(forEachFn, thisArg)

Iterate over all records.

Method parameters:
Name Type Argument Description
forEachFn Function

Iteration function.
thisArg * <optional>

Context to which to bind forEachFn.
Return value:
Type Description
Array

The result.
Details
Since Source
3.0.0 Collection.js, line 426
Example 
collection.forEach(function (record) {
  // do something
})

get(id)

Get the record with the given id.

Method parameters:
Name Type Description
id String | Number

The primary key of the record to get.
Return value:
Type Description
Object | Record

The record with the given id.
Details
Since Source
3.0.0 Collection.js, line 444

getAll(keyList, opts)

Find the record or records that match the provided keyLists.

Shortcut for collection.query().getAll(keyList1, keyList2, ...).run()

Method parameters:
Name Type Argument Description
keyList Array <optional>
<repeatable>

Provide one or more keyLists, and all records matching each keyList will be retrieved. If no keyLists are provided, all records will be returned.
opts Object <optional>

Configuration options.

Properties
Name Type Argument Description
index String <optional>

Name of the secondary index to use in the query. If no index is specified, the main index is used.
Return value:
Type Description
Array

The result.
Details
Since Source
3.0.0 Collection.js, line 457
Examples

Get the posts where "status" is "draft" or "inReview"

const posts = collection.getAll('draft', 'inReview', { index: 'status' })

Same as above

const posts = collection.getAll(['draft'], ['inReview'], { index: 'status' })

getIndex(name)

Return the index with the given name. If no name is provided, return the main index. Throws an error if the specified index does not exist.

Method parameters:
Name Type Argument Description
name String <optional>

The name of the index to retrieve.
Details
Since Source
3.0.0 Collection.js, line 482

limit(num)

Limit the result.

Shortcut for collection.query().limit(maximumNumber).run()

Method parameters:
Name Type Description
num Number

The maximum number of records to keep in the result.
Return value:
Type Description
Array

The result.
Details
Since Source
3.0.0 Collection.js, line 498
Example 
const posts = collection.limit(10)

log(level, args)

Log the provided values. By default sends values to console[level].

Method parameters:
Name Type Argument Description
level String

Log level
args * <optional>
<repeatable>

Values to log.
Details
Since Source
3.0.0 Component.js, line 39
Inherited From:

map(mapFn, thisArg)

Apply a mapping function to all records.

Method parameters:
Name Type Argument Description
mapFn Function

Mapping function.
thisArg * <optional>

Context to which to bind mapFn.
Return value:
Type Description
Array

The result of the mapping.
Details
Since Source
3.0.0 Collection.js, line 515
Example 
const names = collection.map(function (user) {
  return user.name
})

mapCall(funcName)

Return the result of calling the specified function on each record in this collection's main index.

Method parameters:
Name Type Description
funcName String

Name of function to call
Return value:
Type Description
Array

The result.
Details
Since Source
3.0.0 Collection.js, line 537

method(result, opts)

Lifecycle hook called by Collection#add. If this method returns a value then Collection#add will return that same value.

Method parameters:
Name Type Description
result Object | Array.<Object> | Record | Array.<Record>

The record or records that were added to this Collection by Collection#add.
opts Object

The opts argument passed to Collection#add.
Details
Since Source
3.0.0 Collection.js, line 264

off(event, listener)

Remove an event listener from this Component. If no listener is provided, then all listeners for the specified event will be removed. If no event is specified then all listeners for all events will be removed.

Method parameters:
Name Type Argument Description
event String <optional>

Name of event to unsubsribe to.
listener Function <optional>

Listener to remove.
Details
Since Source
3.0.0 Component.js, line 79
Inherited From:
Examples

Remove a listener to a single event

collection.off('add', handler)

Remove all listeners to a single event

record.off('change')

Remove all listeners to all events

store.off()

on(event, listener, ctx)

Register a new event listener on this Component.

Method parameters:
Name Type Argument Description
event String

Name of event to subsribe to.
listener Function

Listener function to handle the event.
ctx * <optional>

Optional content in which to invoke the listener.
Details
Since Source
3.0.0 Component.js, line 49
Inherited From:
Examples

Listen for all "afterCreate" events in a DataStore

store.on('afterCreate', (mapperName, props, opts, result) => {
  console.log(mapperName) // "post"
  console.log(props.id) // undefined
  console.log(result.id) // 1234
})
store.create('post', { title: 'Modeling your data' }).then((post) => {
  console.log(post.id) // 1234
})

Listen for the "add" event on a collection

collection.on('add', (records) => {
  console.log(records) // [...]
})

Listen for "change" events on a record

post.on('change', (record, changes) => {
  console.log(changes) // { changed: { title: 'Modeling your data' } }
})
post.title = 'Modeling your data'

query()

Create a new query to be executed against the contents of the collection. The result will be all or a subset of the contents of the collection.

Return value:
Type Description
Query

New query object.
Details
Since Source
3.0.0 Collection.js, line 573
Example

Grab page 2 of users between ages 18 and 30

collection.query()
  .between(18, 30, { index: 'age' }) // between ages 18 and 30
  .skip(10) // second page
  .limit(10) // page size
  .run()

recordId(record)

Return the primary key of the given, or if no record is provided, return the name of the field that holds the primary key of records in this Collection.

Method parameters:
Name Type Argument Description
record Object | Record <optional>

The record whose primary key is to be returned.
Return value:
Type Description
String | Number

Primary key or name of field that holds primary key.
Details
Since Source
3.0.0 Collection.js, line 555

reduce(cb, initialValue)

Reduce the data in the collection to a single value and return the result.

Method parameters:
Name Type Description
cb Function

Reduction callback.
initialValue *

Initial value of the reduction.
Return value:
Type Description
*

The result.
Details
Since Source
3.0.0 Collection.js, line 593
Example 
const totalVotes = collection.reduce(function (prev, record) {
  return prev + record.upVotes + record.downVotes
}, 0)

remove(id, opts)

Remove the record with the given id from this Collection.

Method parameters:
Name Type Argument Description
id String | Number

The primary key of the record to be removed.
opts Object <optional>

Configuration options.
Return value:
Type Description
Object | Record

The removed record, if any.
Details
Since Source
3.0.0 Collection.js, line 612

removeAll(query, opts)

Remove the record selected by "query" from this collection.

Method parameters:
Name Type Argument Default Description
query Object <optional>
 {}

Selection query.

Properties
Name Type Argument Description
where Object <optional>

Filtering criteria.
skip Number <optional>

Number to skip.
limit Number <optional>

Number to limit to.
orderBy Array <optional>

Sorting criteria.
opts Object <optional>

Configuration options.
Return value:
Type Description
Array.<Object> | Array.<Record>

The removed records, if any.
Details
Since Source
3.0.0 Collection.js, line 641

skip(num)

Skip a number of results.

Shortcut for collection.query().skip(numberToSkip).run()

Method parameters:
Name Type Description
num Number

The number of records to skip.
Return value:
Type Description
Array

The result.
Details
Since Source
3.0.0 Collection.js, line 667
Example 
const posts = collection.skip(10)

toJSON(opts)

Return the plain JSON representation of all items in this collection. Assumes records in this collection have a toJSON method.

Method parameters:
Name Type Argument Description
opts Object <optional>

Configuration options.

Properties
Name Type Argument Description
with Array.<String> <optional>

Array of relation names or relation fields to include in the representation.
Return value:
Type Description
Array

The records.
Details
Since Source
3.0.0 Collection.js, line 684

updateIndex(record, opts)

Update a record's position in a single index of this collection. See Collection#updateIndexes to update a record's position in all indexes at once.

Method parameters:
Name Type Argument Description
record Object

The record to update.
opts Object <optional>

Configuration options.

Properties
Name Type Argument Description
index String <optional>

The index in which to update the record's position. If you don't specify an index then the record will be updated in the main index.
Details
Since Source
3.0.0 Collection.js, line 699

updateIndexes(record, opts)

TODO

Method parameters:
Name Type Argument Description
record Object

TODO
opts Object <optional>

Configuration options.
Details
Since Source
3.0.0 Collection.js, line 717