ArangoDB Module
const arangodb = require('@arangodb')
This module should not be confused with the
arangojs JavaScript driver
which can be used to access ArangoDB from outside the database. Although the
APIs share similarities and the functionality overlaps, the two are not
compatible with each other and can not be used interchangeably.
The db object
arangodb.db
The db object represents the current database and lets you access collections
and run queries. For more information see the db object reference.
Examples
const { db } = require('@arangodb');
const thirteen = db._query('RETURN 5 + 8').next();
The aql template tag
arangodb.aql
The aql function is a JavaScript template string handler (or template tag).
It can be used to write complex AQL queries as multi-line strings without
having to worry about bindVars and the distinction between collections
and regular parameters.
To use it just prefix a JavaScript template string (the ones with backticks
instead of quotes) with its import name (e.g. aql) and pass in variables
like you would with a regular template string. The string will automatically
be converted into an object with query and bindVars attributes which you
can pass directly to db._query to execute. If you pass in a collection it
will be automatically recognized as a collection reference
and handled accordingly.
Starting with ArangoDB 3.4 queries generated using the aql template tag can
be used inside other aql template strings, allowing arbitrary nesting. Bind
parameters of nested queries will be merged automatically.
To find out more about AQL see the AQL documentation.
Examples
const filterValue = 23;
const mydata = db._collection('mydata');
const result = db._query(aql`
FOR d IN ${mydata}
FILTER d.num > ${filterValue}
RETURN d
`).toArray();
// nested queries
const color = "green";
const filterByColor = aql`FILTER d.color == ${color}'`;
const result2 = db._query(aql`
FOR d IN ${mydata}
${filterByColor}
RETURN d
`).toArray();
The aql.literal helper
arangodb.aql.literal
The aql.literal helper can be used to mark strings to be inlined into an AQL
query when using the aql template tag, rather than being treated as a bind
parameter.
Any value passed to aql.literal will be treated as part of the AQL query.
To avoid becoming vulnerable to AQL injection attacks you should always prefer
nested aql queries if possible.
Examples
const { aql } = require('@arangodb');
const filterGreen = aql.literal('FILTER d.color == "green"');
const result = db._query(aql`
FOR d IN ${mydata}
${filterGreen}
RETURN d
`).toArray();
The aql.join helper
arangodb.aql.join
The aql.join helper takes an array of queries generated using the aql tag
and combines them into a single query. The optional second argument will be
used as literal string to combine the queries.
const { aql } = require('@arangodb');
// Basic usage
const parts = [aql`FILTER`, aql`x`, aql`%`, aql`2`];
const joined = aql.join(parts); // aql`FILTER x % 2`
// Merge without the extra space
const parts = [aql`FIL`, aql`TER`];
const joined = aql.join(parts, ''); // aql`FILTER`;
// Real world example: translate keys into document lookups
const users = db._collection("users");
const keys = ["abc123", "def456"];
const docs = keys.map(key => aql`DOCUMENT(${users}, ${key})`);
const aqlArray = aql`[${aql.join(docs, ", ")}]`;
const result = db._query(aql`
FOR d IN ${aqlArray}
RETURN d
`).toArray();
// Query:
// FOR d IN [DOCUMENT(@@value0, @value1), DOCUMENT(@@value0, @value2)]
// RETURN d
// Bind parameters:
// @value0: "users"
// value1: "abc123"
// value2: "def456"
// Alternative without `aql.join`
const users = db._collection("users");
const keys = ["abc123", "def456"];
const result = db._query(aql`
FOR key IN ${keys}
LET d = DOCUMENT(${users}, key)
RETURN d
`).toArray();
// Query:
// FOR key IN @value0
// LET d = DOCUMENT(@@value1, key)
// RETURN d
// Bind parameters:
// value0: ["abc123", "def456"]
// @value1: "users"
The query helper
arangodb.query
In most cases you will likely use the aql template handler to create a query
you directly pass to db._query(). To make this even easier ArangoDB provides
the query template handler, which behaves exactly like aql but also directly
executes the query and returns the result cursor instead of the query object:
const { query } = require('@arangodb');
const filterValue = 23;
const mydata = db._collection('mydata');
const result = query`
FOR d IN ${mydata}
FILTER d.num > ${filterValue}
RETURN d
`.toArray();
// Nesting with `aql` works as expected
const { aql } = require('@arangodb');
const filter = aql`FILTER d.num > ${filterValue}`;
const result2 = query`
FOR d IN ${mydata}
${filter}
RETURN d
`.toArray();
It is also possible to pass query options to the query helper (introduced in v3.7.0):
const { query } = require('@arangodb');
const mydata = db._collection('mydata');
const result = query( { fullCount: true } )`
FOR d IN ${mydata}
LIMIT 1
RETURN d
`.data;
The errors object
arangodb.errors
This object provides useful objects for each error code ArangoDB might use in
ArangoError errors. This is helpful when trying to catch specific errors
raised by ArangoDB, e.g. when trying to access a document that does not exist.
Each object has a code property corresponding to the errorNum found on
ArangoError errors.
For a complete list of the error names and codes you may encounter see the appendix on error codes.
Examples
const errors = require('@arangodb').errors;
try {
someCollection.document('does-not-exist');
} catch (e) {
if (e.isArangoError && e.errorNum === errors.ERROR_ARANGO_DOCUMENT_NOT_FOUND.code) {
throw new Error('Document does not exist');
}
throw new Error('Something went wrong');
}
The time function
arangodb.time
This function provides the current time in seconds as a floating point value with microsecond precision.
This function can be used instead of Date.now() when additional precision
is needed.
Examples
const time = require('@arangodb').time;
const start = time();
db._query(someVerySlowQuery);
console.log(`Elapsed time: ${time() - start} secs`);