# Changelog

All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).

This driver uses semantic versioning:

- A change in the bugfix version (e.g. X.Y.0 -> X.Y.1) indicates internal
  changes and should always be safe to upgrade.
- A change in the minor version (e.g. X.1.Z -> X.2.0) indicates additions and
  backwards-compatible changes that should not affect your code.
- A change in the major version (e.g. 1.Y.Z -> 2.0.0) indicates _breaking_
  changes that require changes in your code to upgrade.

## [Unreleased]

### Removed

- Removed `Dict` type from `connection` module

  The `Dict<T>` type was identical to `Record<string, T>` and has been replaced
  with this built-in type across arangojs.

### Changed

- Updated TypeScript to version 4

  This may result in type signatures that are incompatible with TypeScript 3
  being added in future releases (including patch releases).

- [FORK] Added `scripts/test-with-docker` shell script to start a docker instance
  of `arangodb/arangodb` and run tests against it and `npm run test:docker` command.

- [FORK] Fixed ``aql`${db.graph("banana")}` ``

- [FORK] Upgraded dependencies.

### Added

- Added `collection.documents` for fetching multiple documents

- Added support for `fillBlockCache` query option

## [7.5.0] - 2021-04-22

### Added

- Added support for new ArangoDB 3.8 Analyzer types

  This adds the `PipelineAnalyzer`, `AqlAnalyzer`, `GeoJsonAnalyzer`,
  `GeoPointAnalyzer` and `StopwordsAnalyzer` types in TypeScript, as well as
  the Analyzer-specific properties types.

- Added support for new ArangoDB 3.8 `estimates` option for indexes

  This affects the `PersistentIndex`, `HashIndex` and `SkiplistIndex` types
  in TypeScript.

## [7.4.0] - 2021-04-09

### Added

- Implemented `toJSON` methods for `ArangoError` and `HttpError` ([#632](https://github.com/arangodb/arangojs/issues/632))

  This prevents an error where `JSON.stringify` would reliably throw if passed
  an instance of either of these error types generated by arangojs. Note that
  you may still want to implement your own JSON representation logic as system
  errors (e.g. `ECONNREFUSED`) are not wrapped by arangojs and thrown as-is.

### Fixed

- Stack traces are now improved for most errors when using `precaptureStackTraces` ([#722](https://github.com/arangodb/arangojs/issues/722))

  Previously this option would only affect network errors, making it far less
  useful than intended. Now parsing errors, `ArangoError` instances and HTTP
  errors also receive improved error stack traces when this option is enabled.

- Improved performance for `precaptureStackTraces` when no errors occur

  The generated stack is now only accessed on demand, allowing the runtime to
  delay generation of the stack trace string. Previously the stack would always
  be accessed prior to the request being sent, causing a noticeable delay even
  when no error occurs.

- Fixed document selector validation in `collection.edges` and its variants ([#704](https://github.com/arangodb/arangojs/issues/704))

  These methods previously only permitted start vertices that are documents
  within the edge collection itself. This behavior has now been corrected to
  permit start vertices outside the collection, as expected.

## [7.3.0] - 2021-03-08

### Changed

- Changed the default for `agentOptions.scheduling` to `"lifo"`

  This is already the default in Node v15.6 but can reduce latency caused by
  sockets expiring, especially with larger connection pools and infrequent
  requests.

- Removed `keepAlive`-specific throughput optimization

  Previously arangojs would allow `agentOptions.maxSockets * 2` concurrent
  requests, to optimize socket reuse by avoiding idle time. This behavior
  could trigger deadlocks when attempting to perform multiple transactions
  in parallel and only marginally improved throughput in some high-load
  scenarios. The connection pool size now always reflects the value set in
  `agentOptions.maxSockets` regardless of whether `keepAlive` is enabled.

- Changed `agentOptions.maxSockets` default value when using `ROUND_ROBIN`

  As the connection pool is shared across all server connections when using
  `ROUND_ROBIN` load balancing, the default value of `3` is too limiting for
  most scenarios involving multiple coordinators. When passing multiple URLs
  via the `url` option and specifying `ROUND_ROBIN` load balancing, arangojs
  will now default this value to `url.length * 3` instead.

## [7.2.0] - 2020-12-02

### Added

- Added `db.waitForPropagation` method

  This method helps with setting up databases in a cluster scenario by waiting
  for a request to succeed on every known coordinator.

## [7.1.1] - 2020-11-30

This is a maintenance release and contains no bugfixes or features.

## [7.1.0] - 2020-10-16

### Changed

- Killing a cursor now also drains it locally

### Fixed

- Fixed a potential memory leak in cursor batch handling

## [7.0.2] - 2020-09-25

### Fixed

- Fixed incorrect HTTP method call in `patch` method ([#687](https://github.com/arangodb/arangojs/pull/687))

- Fixed empty query results containing `[undefined]` ([#683](https://github.com/arangodb/arangojs/issues/683))

- Fixed `updateByExample` and `replaceByExample` new value parameter name

  Note that these methods are still deprecated. Previously the `newValue`
  parameter was incorrectly called `newData`, which prevented the methods from
  working at all.

## [7.0.1] - 2020-08-21

This is a maintenance release because the initial v7 release did not include
a README file.

## [7.0.0] - 2020-08-21

This is a major release and breaks backwards compatibility.

See [the migration guide](./MIGRATING.md#v6-to-v7) for detailed instructions
for upgrading your code to arangojs v7.

For a detailed list of changes between pre-release versions of v7 see the
[Changelog of the final v7 release candidate](https://github.com/arangodb/arangojs/blob/v7.0.0-rc.2/CHANGELOG.md).

### Removed

#### General

- Removed ArangoDB 2.8 support

  ArangoDB 2.8 has reached End of Life since mid 2018. Version 7 and above
  of arangojs will no longer support ArangoDB 2.8 and earlier.

- Removed Node.js 6/8 support

  As of version 7 arangojs now requires language support for async/await.
  This means arangojs requires Node.js 10 (LTS) or newer to function correctly.

- Removed support for absolute endpoint URLs

  This removes the `isAbsolute` option from the arangojs configuration.

- Removed `ArangoError` re-export

  The type can still be imported directly from the `error` module.

- Removed `statusCode` properties of `ArangoError` and `HttpError`

  Both of these error types still expose the HTTP status code as the `code`
  property. For `ArangoError` the true HTTP status code may be different and
  can still be accessed using the `response.statusCode` property.

#### Database API

- Removed `db.edgeCollection` method

  As arangojs 7 uses the same implementation for document and edge collections,
  this method is no longer necessary. Generic collection objects can still be
  cast to `DocumentCollection` or `EdgeCollection` types in TypeScript.

- Removed `db.truncate` convenience method

  This was a wrapper around `db.listCollections` and `collection.truncate`.
  The behavior of `db.truncate` can still be emulated by calling these methods
  directly.

#### Collection API

- Removed collection `createCapConstraint`, `createHashIndex`,
  `createSkipList`, `createPersistentIndex`, `createGeoIndex` and
  `createFulltextIndex` methods

  These methods are no longer part of the official ArangoDB API and can be
  replaced by using the `collection.ensureIndex` method.

- Removed `save(fromId, toId, edgeData)` method variants

  Methods for creating edges now require the `_to` and `_from` attributes to
  be specified in the edge (document) data and no longer accept these values
  as positional arguments.

- Removed `collection.bulkUpdate` method

  The new method `collection.updateAll` now provides this functionality.

- Removed `collection.edge` method

  This method was previously an alias for `collection.document`.

  The method `graphEdgeCollection.edge` is unaffected by this change.

- Removed `graphName` option for `edgeCollection.traversal`

  Graph traversals can still be performed via `graph.traversal`.

#### Graph API

- Removed generic collection methods from `GraphVertexCollection`

  All methods that are not part of the graph API have been removed.
  The underlying collection can still be accessed from the `collection`
  property.

- Removed generic collection methods from `GraphEdgeCollection`

  All methods that are not part of the graph API have been removed.
  The underlying collection can still be accessed from the `collection`
  property.

#### Cursor API

- Removed `cursor.some` and `cursor.every` methods

  These methods encouraged overfetching and should be replaced with more
  efficient AQL queries.

  The behavior can still be implemented by using the `next` method directly
  or iterating over the cursor using the `forEach` method or the `for await`
  syntax.

#### View API

- Removed `ViewResponse` type

  The type `ViewDescription` represents the same structure.

- Removed `ArangoSearchViewPropertiesResponse` type

  The type `ArangoSearchViewProperties & ViewDescription` can be used
  to represent the same structure.

### Deprecated

#### Database API

- Deprecated `db.useDatabase` method

  Using this method will affect `Collection`, `Graph` and other objects
  already created for the given database and change which database these
  refer to, which may cause unexpected behavior.

  As of arangojs 7 the `db.database` method can be used instead to create a
  new, separate `Database` object using the same connection pool.

#### Collection API

- Deprecated `Collection` methods for simple queries: `list`, `all`, `any`,
  `byExample`, `firstExample`, `removeByExample`, `replaceByExample`,
  `updateByExample`, `lookupByKeys`, `removeByKeys`, `fulltext`

  These methods were deprecated in ArangoDB 3.4 and should no longer be used.
  They will still behave correctly with versions of ArangoDB supporting these
  methods but may be removed in a future ArangoDB release.

  Their behavior can be emulated using AQL queries.

#### Graph API

- Deprecated `graph.traversal` and `collection.traversal`

  These methods were deprecated in ArangoDB 3.4 and should no longer be used.
  They will still behave correctly with versions of ArangoDB supporting these
  methods but may be removed in a future ArangoDB release.

  Their behavior can be emulated using AQL graph traversal.

### Changed

#### General

- Multiple `Database` objects can now share a single `Connection`

  All arangojs objects now reference a `Database` object rather than accessing
  the underlying `Connection` directly. This allows multiple `Database` objects
  to be created by using the `db.database` method while still allowing the
  creation of separate database objects with separate connection pools if
  desired.

- Memoized `Database`, `Collection`, `Graph`, `View` and `Analyzer`

  Database objects are now memoized per-connection and the other object types
  are memoized per-database. Using `useDatabase` de-memoizes the database
  object to prevent unexpected behavior.

- Added support for `View` in `aql` templates ([#667](https://github.com/arangodb/arangojs/issues/667))

  `View` (or `ArangoSearchView`) objects can now be passed into `aql` templates
  like `ArangoCollection` objects.

- Moved `collectionToString` helper into `collection` module

- Moved `Dict` type into `connection` module

- Moved `Patch` type into `documents` module

- Removed `Errback` type from public API

- Renamed `util/foxx-manifest` module to `foxx-manifest`

#### Database API

- Renamed method `db.arangoSearchView` to `db.view`

- Renamed method `db.createArangoSearchView` to `db.createView`

- Replaced methods `db.enableServiceDevelopmentMode` and
  `db.disableServiceDevelopmentMode` with `db.setServiceDevelopmentMode`

- Flattened database `query` method `options` argument

  The optional `options` argument previously contained an additional `options`
  object with additional query options. These options are now specified on the
  `options` argument itself directly.

  Before:

  ```js
  db.query(aql`FOR doc IN ${collection} RETURN doc`, {
    cache: false,
    options: { fullCount: true },
  });
  ```

  After:

  ```js
  db.query(aql`FOR doc IN ${collection} RETURN doc`, {
    cache: false,
    fullCount: true,
  });
  ```

- Changed `db.listServices` option `excludeSystem` default to `true`

  To be more consistent with the equivalent options in other methods,
  the default value has been changed from `false` to `true`.

- Changed `db.createDatabase` return type to `Database`

- Renamed `database.setQueryTracking` to `database.queryTracking`

  The method will now return the existing query tracking properties or set the
  new query tracking properties depending on whether an argument is provided.

- Method `db.transaction` no longer acts as an alias for `executeTransaction`

  The method now only allows looking up transactions by ID. Previously it would
  wrap `executeTransaction` if passed the arguments expected by that method.

#### Collection API

- Merged `DocumentCollection` and `EdgeCollection` APIs

  All collections are now implemented as generic `Collection` objects.
  In TypeScript the generic collection object can still be explicitly cast to
  `DocumentCollection` or `EdgeCollection` for stricter type safety.

- Renamed `collection.setProperties` to `collection.properties`

  The method will now return the existing properties or set the properties
  depending on whether an argument is provided.

- Removed `CollectionMetadata` fields from `CollectionProperties` type

  Methods that previously returned `CollectionProperties` now return
  `CollectionMetadata & CollectionProperties`.

- Collection methods `save`, `update`, `replace` and `remove` no longer take
  arrays as input

  The array versions have been renamed to `saveAll`, `updateAll`, `replaceAll`
  and `removeAll` to reduce the likelihood of mistakes and provide more helpful
  type signatures.

- Collection methods will now throw errors when passed documents or document
  IDs from different collections where a document key or ID for a document in
  the same collection is expected

  For example the following code will now result in an error rather than the
  document from a different collection being returned:

  ```js
  const aliceId = "alice/123"; // Document from collection "alice"
  const bobCol = db.collection("bob"); // Collection "bob"
  const doc = await bobCol.document(aliceId); // THROWS
  ```

- Changed `collection.import` option `type` behavior

  Previously this option would always default to `"auto"`.

  When passing a `string`, `Buffer` or `Blob` as data, the option now defaults
  to `undefined`. This matches the behavior in previous versions of setting
  the option explicitly to `null`.

  Additionally, the value `"array"` has been replaced with `"list"`.

  When passing an array as data, the option is now no longer supported as the
  corresponding value will be inferred from the array's contents:

  If the array's first item is also an array, it will match the behavior in
  previous versions of setting the option explicitly to `null`.

  Otherwise it will match the behavior in previous versions of setting the
  option explicitly to `"documents"` or `"auto"`, or omitting it entirely.

- Changed `collection.list` return type to `ArrayCursor`

#### Graph API

- Graph methods now also accept `ArangoCollection` instances instead of names

  This brings these methods behavior in line with that of the `beginTransaction`
  and `executeTransaction` methods of `Database` objects.

- Graph `create` method (and `db.createGraph`) signature changed

  The `graph.create` method now takes an array of edge definitions as the
  first argument and any additional options (not just the `waitForSync`
  option) as the second argument.

  Before:

  ```js
  await graph.create(
    {
      edgeDefinitions: [{ collection: "edges", from: ["a"], to: ["b"] }],
      isSmart: true,
    },
    { waitForSync: true }
  );
  ```

  After:

  ```js
  await graph.create([{ collection: "edges", from: ["a"], to: ["b"] }], {
    isSmart: true,
    waitForSync: true,
  });
  ```

- First argument to `graph.replaceEdgeDefinition` is now optional

  Since the new edge definition already includes the edge collection name
  that identifies the edge definition, it is now possible to specify only the
  new edge definition object without additionally specifying the collection
  name as the first argument.

  Before:

  ```js
  await graph.replaceEdgeDefinition("edges", {
    collection: "edges", // This is a bit redundant
    from: ["a"],
    to: ["b"],
  });
  ```

  After:

  ```js
  await graph.replaceEdgeDefinition({
    collection: "edges",
    from: ["a"],
    to: ["b"],
  });
  ```

- Graph collection return values now contain `old` and `new` properties when
  `returnOld` or `returnNew` options are used

  This behavior represents a compromise between remaining consistent with the
  behavior of the regular collection method equivalents and remaining
  compatible with the ArangoDB HTTP API response object quirks.

#### Cursor API

- Replaced `ArrayCursor` methods `hasNext` and `hasMore` with getters

- Renamed `ArrayCursor` method `each` to `forEach`

- Renamed `cursor.nextBatch` to `cursor.batches.next`

- Renamed `cursor.hasMore` to `cursor.batches.hasMore`

- In TypeScript `ArrayCursor` is now a generic type

  TypeScript users can now cast cursor instances to use a specific type for
  its values rather than `any` to aid type safety.

#### View API

- Renamed `view.setProperties` to `view.updateProperties`

- Renamed type `ArangoView` to `View`

#### Analyzer API

- Renamed type `ArangoAnalyzer` to `Analyzer`

#### Transaction API

- Renamed type `ArangoTransaction` to `Transaction`

- Renamed `transaction.run` to `transaction.step`

  This should hopefully make it more obvious that sequential calls to arangojs
  methods should be split into separate calls of this method.

### Added

#### General

- Added `databaseName` configuration option

  Setting this option to a database name will result in the initial `Database`
  object using this database instead of the default `_system` database.

- Added `auth` configuration option

  It is now possible to pass authentication credentials using the `auth`
  option in addition to calling `db.useBasicAuth` or `db.useBearerAuth`.

- Added `precaptureStackTraces` configuration option ([#599](https://github.com/arangodb/arangojs/issues/599))

  This option can be used to get more useful stack traces but results in a
  performance hit on every request.

- Added `before` and `after` to the `agentOptions` configuration option ([#585](https://github.com/arangodb/arangojs/issues/585))

  These methods can be used to track performance metrics for outgoing requests.

- Improved type signatures for TypeScript and inline documentation

  Most methods should now provide full type signatures for options and response
  objects and provide inline documentation in IDEs and editors that support
  this feature in TypeScript and JavaScript.

#### Database API

- Added `db.database` method

  This method replaces the use case for the deprecated `db.useDatabase`
  method.

- Added support for extended options in `db.createDatabase`

  This method now supports passing an extended options object instead of
  passing the users array directly.

- Added `db.createCollection` and `db.createEdgeCollection` methods

  These are convenience methods wrapping `collection.create`. In TypeScript
  `createEdgeCollection` will return a collection cast to the `EdgeCollection`
  type.

- Added `db.createGraph` method

  This is a convenience method wrapping `graph.create`.

- Added `db.createArangoSearchView` method

  This is a convenience method wrapping `view.create`.

- Added `db.createAnalyzer` method

  This is a convenience method wrapping `analyzer.create`.

- Added support for `db.createFunction` option `isDeterministic`

- Added support for `db.listServices` option `excludeSystem`

#### Collection API

- Added collection `saveAll`, `updateAll`, `replaceAll` and `removeAll` methods

  These methods replace the respective array versions of the collection
  methods `save`, `update`, `replace` and `remove`, which no longer accept
  arrays as inputs.

- Added `collection.documentId` method

  The method takes a document or a document key and returns a fully qualified
  document ID string for the document in the current collection.

- Added support for values `"ignore"` and `"conflict"` in `overwriteMode`
  option when saving documents using the Collection API

#### Graph API

- Added `graphVertexCollection.vertexExists` and
  `graphEdgeCollection.edgeExists` methods

  These mimic the behavior of the `collection.documentExists` method but using
  the Graph API.

- Added `graphVertexCollection.collection` and `graphEdgeCollection.collection`

  These properties now provide access to regular (non-graph) collection
  objects for these graph collections. These objects can be used to perform
  operations not available within the context of a graph (e.g. bulk imports
  or modifying the collection itself).

- Added support for `isDisjoint` option in Graph API

#### Cursor API

- Added `cursor.flatMap` method

  This method behaves similarly to the `Array` method `flatMap` but operates
  on the cursor directly like `cursor.map` does.

- Added `cursor.batches` to provide a batch-wise cursor API

- Added support for `for await` in `ArrayCursor` ([#616](https://github.com/arangodb/arangojs/pull/616))

  It is now possible to use `for await` to iterate over each item in a cursor
  asynchronously.

#### View API

- Added support for `primarySortCompression` and `storedValues` options in
  View API

### Fixed

#### General

- Removed TypeScript dependency on `dom` library

  If you are using arangojs in Node.js, you no longer need to add the `dom`
  library to your `tsconfig.json` configuration.

#### Database API

- Fixed `db.dropFunction` option `group` being ignored

- Fixed documentation of `db.runServiceTests`

  Previously the documentation incorrectly indicated that the default value
  of the `idiomatic` option is `true`. The correct default value is `false`.

## [6.14.1] - 2020-05-01

### Fixed

- Added `uuid` and `padded` to legal `KeyGeneratorType` values in TypeScript ([#656](https://github.com/arangodb/arangojs/issues/656))

- Added `overwrite` to `InsertOptions` type in TypeScript ([#657](https://github.com/arangodb/arangojs/issues/657))

## [6.14.0] - 2020-03-18

### Added

- Added `db.listTransactions` and `db.transactions` methods

## [6.13.0] - 2020-01-24

### Changed

- Empty querystring parameters are now omitted

  In some cases ArangoDB would be unable to correctly handle querystring
  parameters without values. Any paremeters set to `undefined` will now
  no longer be added to the querystring.

  This does not affect parameters set to empty string values.

### Added

- Added `maxRuntime` option to `db.query` method

### Fixed

- Replaced `linkedlist` dependency with `x3-linkedlist` ([#601](https://github.com/arangodb/arangojs/issues/601))

  The `linkedlist` dependency had a memory leak and was no longer maintained.
  The replacement should fix this issue.

## [6.12.0] - 2019-10-16

### Added

- Added `cursor.kill` method

  Cursors that have not yet been fully depleted can now be killed using the
  `cursor.kill` method. Note that this method has no effect if the cursor
  is already depleted.

- Added `cursor.nextBatch` method

  Cursors normally fetch additional batches as necessary while iterating
  over the individual results, this method allows consuming an entire batch
  at a time.

## [6.11.1] - 2019-08-30

### Fixed

- Fixed View properties not being passed correctly when creating Views ([#621](https://github.com/arangodb/arangojs/issues/621))

- Renamed internal `response.host` attribute to `response.arangojsHostId` ([#604](https://github.com/arangodb/arangojs/pull/604))

  In some environments the `host` attribute is already present and read-only.
  This should avoid a `TypeError` being thrown when a value is assigned by
  arangojs.

## [6.11.0] - 2019-08-16

### Changed

- Renamed `db.transaction` to `db.executeTransaction`

  The method for executing server-side transactions is now called
  `executeTransaction` and the `params` argument now must be passed via the
  `options` object.

  For backwards-compatibility the new `db.transaction` method will continue to
  behave like before when passed an `action` string as the second argument.
  Note that this behavior is deprecated and will be removed in arangojs 7.

### Added

- Added support for ArangoDB 3.5 streaming transactions

  New streaming transactions can be created using `db.beginTransaction` and
  existing streaming transactions can be accessed by passing the transaction ID
  to `db.transaction`.

  See the documentation of the `transaction.run` method for examples of using
  streaming transactions with arangojs.

- Added support for ArangoDB 3.5 Analyzers API

  See the documentation of the `database.analyzer` method and the `Analyzer`
  instances for information on using this API.

- Added `collection.getResponsibleShard` method

- Added support for new ArangoDB 3.5 collection properties

- Added support for new ArangoDB 3.5 View properties

### Fixed

- Fixed a problem causing empty nested AQL expressions to be converted to bind variables

  Nesting an empty AQL expression like the result of calling `aql.join` with an empty
  array would previously result in the AQL expression not being recognized and being
  converted to an object bind variable instead.

## [6.10.0] - 2018-12-22

### Changed

- Changed Views API to match 3.4 GA implementation

  This release updates the Views API to the version implemented in the final
  ArangoDB 3.4 GA release. Please note that these changes may break code
  written for earlier ArangoDB 3.4 release candidates.

### Added

- Added `timeout` option to `db.query` and request methods ([#572](https://github.com/arangodb/arangojs/issues/572))

  Note that this merely cancels the request. Queries will still be executed
  and ArangoDB will still continue processing the request, this will merely
  result in the socket being forcefully disconnected.

- Added query management API ([#474](https://github.com/arangodb/arangojs/issues/474))

  This implements most endpoints of the
  [HTTP Interface for AQL Queries](https://www.arangodb.com/docs/stable/http/aql-query.html).

## [6.9.0] - 2018-11-07

### Changed

- Restored support for credentials in URLs

  If the server URL includes credentials, arangojs will now use them instead of
  the default username "root" and an empty password. Any credentials explicitly
  set using `useBasicAuth` or `useBearerAuth` will still override the default
  credentials as before.

## [6.8.0] - 2018-11-07

### Changed

- Added `any[]` to allowed types for AQL bind parameters

  This should help in some cases where the previous TypeScript annotation
  was too restrictive.

### Added

- Added support for UNIX socket URLs ([#405](https://github.com/arangodb/arangojs/issues/405))

  In addition to the `unix:///socket/path` and `http+unix:///socket/path`
  URL formats recognized by ArangoDB, arangojs also supports the format
  `http://unix:/socket/path` commonly supported in the Node ecosystem and
  automatically converts ArangoDB endpoint URLs between them.

## [6.7.0] - 2018-10-24

### Changed

- No longer emitting `undefined` values in `aql` template strings

  Previously using `undefined` values in an aql template string would result
  in a bind parameter being added with no value, which would always lead to an
  error response when ArangoDB executes the query.
  Now undefined values will simply be omitted, also easing the conditional
  insertion of query fragments.

- Changed experimental Views API

  This release updates the experimental support for the Views API to the version
  implemented in the ArangoDB 3.4 release candidate. Please note that this API
  is still subject to change and may indeed still change until the 3.4.0 GA release.

- Updated TypeScript to version 3

  This may result in type signatures that are incompatible with TypeScript 2
  being added in future releases (including patch releases).

### Added

- Added nesting support for `aql` template strings ([#481](https://github.com/arangodb/arangojs/issues/481))

  It is now possible to use aql queries as values in `aql` template strings:

  ```js
  function createQuery(flowers, color) {
    const filter = color ? aql`FILTER flower.color == ${color}` : undefined;
    return aql`FOR flower IN ${flowers} ${filter} RETURN flower`;
  }
  createQuery(db.collection("flowers", "green"));
  // FOR flower IN @@value0 FILTER @value1 RETURN flower
  // {"@value0": "flowers", "value1": "green"}
  createQuery(db.collection("flowers"));
  // FOR flower IN @@value0  RETURN flower
  // {"@value0": "flowers"}
  ```

  Previously aql fragments could only be created with `aql.literal`, which
  does not support bind parameters:

  ```js
  aql.literal("FILTER flower.color == " + JSON.stringify(color));
  // Note that we had to rely on JSON.stringify to correctly escape the value
  // because the value is part of the literal, not a bind parameter
  ```

- Added support for `undefined` and AQL literals to `aql.literal`

  Passing undefined to `aql.literal` will now result in an empty literal as
  would be expected. Passing an AQL literal back into `aql.literal` will return
  the existing literal rather than the string `[object Object]`.

- Added `aql.join` function

  The function `aql.join` can be used to convert an array of `aql` queries into
  a combined query:

  ```js
  const users = db.collection("users");
  const keys = ["a", "b", "c"];
  const fragments = keys.map((key) => aql`DOCUMENT(${users}, ${key})`);
  const combined = aql`[${aql.join(fragments, ", ")}]`;
  // [DOCUMENT(@@value0, @value1), DOCUMENT(@@value0, @value2), \
  // DOCUMENT(@@value0, @value3)]
  // {"@value0": "users", "value1": "a", "value2": "b", "value3": "c"}
  const query = aql`FOR user IN ${combined} RETURN user.email`;
  // FOR user IN [DOCUMENT(@@value0, @value1), DOCUMENT(@@value0, @value2), \
  // DOCUMENT(@@value0, @value3)] RETURN user.email
  // {"@value0": "users", "value1": "a", "value2": "b", "value3": "c"}
  ```

- Added `allowDirtyRead` option to `db.query` and `collection.document`

  Dirty reads are supported in leader/follower replication setups and require
  ArangoDB 3.4 or later. When performing a request that permits dirty reads,
  arangojs will load balance across all know leaders and followers and instruct
  ArangoDB to allow responding with stale or dirty response data. Note that
  data returned from a dirty read may be out of date or inconsistent.

## [6.6.0] - 2018-08-28

### Changed

- Re-implemented `collection.import`

  The previous implementation was broken. The new implementation should be backwards-compatible
  in cases where it previously wasn't broken but is more flexible and also handles buffers.

### Fixed

- Added missing dependency on `@types/node` ([#567](https://github.com/arangodb/arangojs/issues/567))

  This should solve TypeScript errors when the dependency was not already added.

## [6.5.1] - 2018-08-15

### Fixed

- Fixed `edgeCollection.save` not respecting options ([#554](https://github.com/arangodb/arangojs/issues/554))

- Fixed `database.createDatabase` TypeScript signature ([#561](https://github.com/arangodb/arangojs/issues/561))

## [6.5.0] - 2018-08-03

### Changed

- Requests that fail because a server can not be reached are now automatically
  retried if other servers are available

  This behavior can be controlled using the `maxRetries` option.

- Renamed `EdgeCollection#edge` to `EdgeCollection#document`

  `EdgeCollection#edge` is now an alias for the `document` method.

- Renamed `GraphEdgeCollection#edge` to `GraphEdgeCollection#document`

  `GraphEdgeCollection#edge` is now an alias for the `document` method.

- Renamed `GraphVertexCollection#vertex` to `GraphVertexCollection#document`

  `GraphVertexCollection#vertex` is now an alias for the `document` method.

### Added

- Added `maxRetries` option to configuration to control retry behavior

- Added `collection.documentExists` method

- Added `graceful` option to `collection.document`

## [6.4.0] - 2018-07-06

### Changed

- Added TypeScript validation for `opts` in `DocumentCollection#save`

### Added

- Added `ArangoError` and `CollectionType` to public exports

- Added `database.close` method

- Added `opts` parameter to `EdgeCollection#save`

## [6.3.0] - 2018-06-20

### Added

- Added `database.version` method

- Added `database.login` method

- Added `database.exists` method

- Added `collection.exists` method

- Added `graph.exists` method

- Added `aql.literal` function

- Exposed typings for collections and graphs ([@samrg472](https://github.com/samrg472) in [#538](https://github.com/arangodb/arangojs/pull/538))

### Fixed

- Fixed synchronous errors during request creation not being handled

  Internal errors thrown while a request is created (e.g. malformed URIs) would
  result in unhandled errors, which could result in termination of the process
  or promises never being rejected. These errors are now handled normally and
  will result in async rejections as expected.

## [6.2.4] - 2018-04-27

### Fixed

- Ensure `res.body` is an empty string instead of null in the browser version

## [6.2.3] - 2018-04-03

### Fixed

- Fixed `collection.update(documentHandle, newValue, opts)` missing return value

- Fixed `collection.removeByKeys(keys, options)` missing return value

- Fixed `collection.replaceByExample(example, newValue, opts)` missing return value

- Fixed `collection.updateByExample(example, newValue, opts)` missing return value

## [6.2.2] - 2018-03-21

### Fixed

- Replaced `Object.values` use to improve Node version compatibility

  This allows using arangojs in Node.js 6 LTS without a polyfill.

## [6.2.1] - 2018-03-21

### Changed

- Moved most documentation out of the README ([#123](https://github.com/arangodb/arangojs/issues/123))

  This is a necessary step to integrate arangojs with the Drivers book in the official ArangoDB documentation.

- Replaced internal use of async functions with callbacks

  This removes some unnecessary layers of indirection, which should increase overall performance.

### Fixed

- Increased test coverage ([#34](https://github.com/arangodb/arangojs/issues/34)).

## [6.2.0] - 2018-03-06

### Changed

- Extended `db.transaction` arguments ([@f5io](https://github.com/f5io) in [#494](https://github.com/arangodb/arangojs/pull/494))

  It's now possible to pass additional transaction options.

### Fixed

- Fixed `db.acquireHostList` request path ([@jcambass](https://github.com/jcambass) in [#504](https://github.com/arangodb/arangojs/pull/504))

- Fixed a typo ([@lodestone](https://github.com/lodestone) in [#506](https://github.com/arangodb/arangojs/pull/506))

- Fixed `graphEdgeCollection.edge` return value ([@Hunter21007](https://github.com/Hunter21007) in [#501](https://github.com/arangodb/arangojs/pull/501))

- Fixed graph API sending incorrect requests resulting in HTTP 400 errors ([@casdevs](https://github.com/casdevs) in [#513](https://github.com/arangodb/arangojs/pull/513))

## [6.1.0] - 2018-02-12

### Removed

- Removed ES modules build

  This should solve compatibility problems with `es6-error`. The cjs
  build now should also work with emulated ES module imports.

### Changed

- Use `cpy-cli` for build process

  Should help with cross-platform compatibility.

### Fixed

- Fixed `db.uninstallService(mount, opts)` opts default value

- Fixed `db.getServiceConfiguration(mount, minimal)` minimal representation

- Fixed `db.getServiceDependencies(mount, minimal)` minimal representation

- Fixed `db.updateServiceConfiguration(mount, cfg, minimal)` non-minimal representation

- Fixed `db.replaceServiceConfiguration(mount, cfg, minimal)` non-minimal representation

- Fixed `db.updateServiceDependencies(mount, cfg, minimal)` non-minimal representation

- Fixed `db.replaceServiceDependencies(mount, cfg, minimal)` non-minimal representation

- Fixed handling of non-json responses

## [6.0.1] - 2018-01-22

### Changed

- Use `rimraf` for build process

  Should help with cross-platform compatibility.

### Fixed

- Fixed some imports broken during the TypeScript rewrite

  If you were previously seeing errors involving a `default` property,
  this should make those go away.

## [6.0.0] - 2018-01-11

### Removed

- Removed `retryConnection` config.

  It is not possible to reliably determine whether retrying a request
  is safe or not at the driver level. If you need automatic retry, you
  should implement your own logic, e.g. using the
  [retry](https://yarnpkg.com/en/package/retry) package.

- Removed `promise` config.

  If you want to use an alternative promise implementation
  you need to overwrite the `Promise` global variable directly.

- Asynchronous functions no longer support node-style callbacks.

  All asynchronous functions now return promises.

- Removed support for credentials in `url` config.

  Use `db.useBasicAuth` or `db.useBearerAuth` to pass credentials instead.

- Removed bower support.

  Use yarn/npm instead.

### Changed

- Removed `lib` path prefix

  All arangojs files can now be imported directly by name.

  Before:

  ```js
  import { DocumentCollection } from "arangojs/lib/collection";
  ```

  After:

  ```js
  import { DocumentCollection } from "arangojs/collection";
  ```

- The `url` config can now also be an array of URLs.

  The behavior depends on the load balancing strategy (see API docs).

- The `databaseName` config has been replaced with `isAbsolute`.

  If you previously used `databaseName: false`, the same behavior can now
  be achieved using `isAbsolute: true`. If you want to use a specific
  database you can still switch databases with `db.useDatabase` at any time.

- Browser: maximum number of parallel connections behaves differently.

  As keep-alive does not work reliably in the browser, the maximum number
  of parallel connections now matches `agentOptions.maxSockets` exactly.

- TypeScript: ported arangojs to TypeScript.

  The generated typings are now included in the NPM release and should
  be more reliable than the community maintained typings included with
  earlier versions of arangojs.
  See also [#480](https://github.com/arangodb/arangojs/issues/480).

### Added

- Added ES Modules and browser build to NPM release.

  - ES Modules files live under `lib/esm/`
  - CommonJS files live under `lib/cjs/`
  - Precompiled browser build lives at `lib/web.js`

- Added support for load balancing and failover.

  See API documentation for details.

- Added `acquireHostList` method.

  See API documentation for details.

- Added support for leader/follower failover.

  Connections to a follower responding with an endpoint redirect
  will now be transparently redirected to the indicated leader.

### Fixed

- Fixed [#354](https://github.com/arangodb/arangojs/issues/354)

  Graph methods now only return the relevant part of the response body.

[unreleased]: https://github.com/arangodb/arangojs/compare/v7.5.0...HEAD
[7.5.0]: https://github.com/arangodb/arangojs/compare/v7.4.0...v7.5.0
[7.4.0]: https://github.com/arangodb/arangojs/compare/v7.3.0...v7.4.0
[7.3.0]: https://github.com/arangodb/arangojs/compare/v7.2.0...v7.3.0
[7.2.0]: https://github.com/arangodb/arangojs/compare/v7.1.1...v7.2.0
[7.1.1]: https://github.com/arangodb/arangojs/compare/v7.1.0...v7.1.1
[7.1.0]: https://github.com/arangodb/arangojs/compare/v7.0.2...v7.1.0
[7.0.2]: https://github.com/arangodb/arangojs/compare/v7.0.1...v7.0.2
[7.0.1]: https://github.com/arangodb/arangojs/compare/v7.0.0...v7.0.1
[7.0.0]: https://github.com/arangodb/arangojs/compare/v6.14.1...v7.0.0
[6.14.1]: https://github.com/arangodb/arangojs/compare/v6.14.0...v6.14.1
[6.14.0]: https://github.com/arangodb/arangojs/compare/v6.13.0...v6.14.0
[6.13.0]: https://github.com/arangodb/arangojs/compare/v6.12.0...v6.13.0
[6.12.0]: https://github.com/arangodb/arangojs/compare/v6.11.1...v6.12.0
[6.11.1]: https://github.com/arangodb/arangojs/compare/v6.11.0...v6.11.1
[6.11.0]: https://github.com/arangodb/arangojs/compare/v6.10.0...v6.11.0
[6.10.0]: https://github.com/arangodb/arangojs/compare/v6.9.0...v6.10.0
[6.9.0]: https://github.com/arangodb/arangojs/compare/v6.8.0...v6.9.0
[6.8.0]: https://github.com/arangodb/arangojs/compare/v6.7.0...v6.8.0
[6.7.0]: https://github.com/arangodb/arangojs/compare/v6.6.0...v6.7.0
[6.6.0]: https://github.com/arangodb/arangojs/compare/v6.5.1...v6.6.0
[6.5.1]: https://github.com/arangodb/arangojs/compare/v6.5.0...v6.5.1
[6.5.0]: https://github.com/arangodb/arangojs/compare/v6.4.0...v6.5.0
[6.4.0]: https://github.com/arangodb/arangojs/compare/v6.3.0...v6.4.0
[6.3.0]: https://github.com/arangodb/arangojs/compare/v6.2.4...v6.3.0
[6.2.4]: https://github.com/arangodb/arangojs/compare/v6.2.3...v6.2.4
[6.2.3]: https://github.com/arangodb/arangojs/compare/v6.2.2...v6.2.3
[6.2.2]: https://github.com/arangodb/arangojs/compare/v6.2.1...v6.2.2
[6.2.1]: https://github.com/arangodb/arangojs/compare/v6.2.0...v6.2.1
[6.2.0]: https://github.com/arangodb/arangojs/compare/v6.1.0...v6.2.0
[6.1.0]: https://github.com/arangodb/arangojs/compare/v6.0.1...v6.1.0
[6.0.1]: https://github.com/arangodb/arangojs/compare/v6.0.0...v6.0.1
[6.0.0]: https://github.com/arangodb/arangojs/compare/v5.8.0...v6.0.0