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`IsIndex`

This reference topic applies to FQL v4. Go to this page for the latest FQL v10 reference topics.

IsIndex( value )

is_index( value )

IsIndex( value )

IsIndex( value )

IsIndex( value )

Description

The IsIndex function returns true only if value is an index, otherwise it returns false.

Parameters

Parameter Type Definition and Requirements

Parameter	Type	Definition and Requirements
`value`	Any	Any value, which is to be tested to determine whether it is an index or not.

value

Any

Any value, which is to be tested to determine whether it is an index or not.

Returns

Returns a boolean, indicating whether value was an index or not.

Examples

The following query uses Map to iterate over an array of all of the types of values that can be tested by a type-check function, passing each item into a Lambda function that returns an object, which contains the value and the result of calling IsIndex with that value:

client.query(
  q.Map(
    [
      ['array'],
      true,
      false,
      new Uint8Array([1, 2, 3, 4]),
      [0x1, 0x2, 0x3, 0x4],
      q.Collection('Letters'),
      q.Ref('credentials/self'),
      q.Database('child_db'),
      q.Date('2019-11-12'),
      q.Ref(q.Collection('Letters'), 123),
      10.1,
      q.Function('double'),
      q.Index('letters'),
      10,
      q.Ref(q.Keys(), '1'),
      q.Query(q.Lambda('x', q.Var('x'))),
      null,
      { x: 10 },
      q.Role('employees'),
      q.Match(q.Index('letters')),
      'ten',
      '10',
      q.Time('2020-07-06T12:34:56.789Z'),
      q.Ref(q.Tokens(), '1'),
    ],
    q.Lambda('x', {
      value: q.Var('x'),
      IsIndex: q.IsIndex(q.Var('x')),
    })
  )
)
.then((ret) => console.log(ret))
.catch((err) => console.error(
  'Error: [%s] %s: %s',
  err.name,
  err.message,
  err.errors()[0].description,
))

[
  { value: [ 'array' ], IsIndex: false },
  { value: true, IsIndex: false },
  { value: false, IsIndex: false },
  { value: Bytes("AQIDBA=="), IsIndex: false },
  { value: [ 1, 2, 3, 4 ], IsIndex: false },
  { value: Collection("Letters"), IsIndex: false },
  { value: Ref(Credentials(), "268432497668260352"), IsIndex: false },
  { value: Database("child_db"), IsIndex: false },
  { value: Date("2019-11-12"), IsIndex: false },
  { value: Ref(Collection("Letters"), "123"), IsIndex: false },
  { value: 10.1, IsIndex: false },
  { value: Function("double"), IsIndex: false },
  { value: Index("letters"), IsIndex: true },
  { value: 10, IsIndex: false },
  { value: Ref(Keys(), "1"), IsIndex: false },
  { value: Query(Lambda("x", Var("x"))), IsIndex: false },
  { value: null, IsIndex: false },
  { value: { x: 10 }, IsIndex: false },
  { value: Role("employees"), IsIndex: false },
  { value: Match(Index("letters")), IsIndex: false },
  { value: 'ten', IsIndex: false },
  { value: '10', IsIndex: false },
  { value: Time("2020-06-15T21:20:29.897Z"), IsIndex: false },
  { value: Ref(Tokens(), "1"), IsIndex: false }
]

result = client.query(
  q.map_(
    q.lambda_("x", {
      "value": q.var("x"),
      "IsIndex": q.is_index(q.var("x")),
    }),
    [
      ["array"],
      True,
      False,
      bytearray([1, 2, 3, 4]),
      [0x1, 0x2, 0x3, 0x4],
      q.collection("Letters"),
      q.ref("credentials/self"),
      q.database("child_db"),
      q.date("2019-11-12"),
      q.ref(q.collection("Letters"), 123),
      10.1,
      q.function("double"),
      q.index("letters"),
      10,
      q.ref(q.keys(), "1"),
      q.query(q.lambda_("x", q.var("x"))),
      None,
      {"x": 10},
      q.role("employees"),
      q.match(q.index("letters")),
      "ten",
      "10",
      q.time("2020-07-06T12:34:56.789Z"),
      q.ref(q.tokens(), "1"),
    ],
  )
)
print(result)

[{'value': ['array'], 'IsIndex': False}, {'value': True, 'IsIndex': False}, {'value': False, 'IsIndex': False}, {'value': bytearray(b'\x01\x02\x03\x04'), 'IsIndex': False}, {'value': [1, 2, 3, 4], 'IsIndex': False}, {'value': Ref(id=Letters, collection=Ref(id=collections)), 'IsIndex': False}, {'value': Ref(id=282032258185953792, collection=Ref(id=credentials)), 'IsIndex': False}, {'value': Ref(id=child_db, collection=Ref(id=databases)), 'IsIndex': False}, {'value': datetime.date(2019, 11, 12), 'IsIndex': False}, {'value': Ref(id=123, collection=Ref(id=Letters, collection=Ref(id=collections))), 'IsIndex': False}, {'value': 10.1, 'IsIndex': False}, {'value': Ref(id=double, collection=Ref(id=functions)), 'IsIndex': False}, {'value': Ref(id=letters, collection=Ref(id=indexes)), 'IsIndex': True}, {'value': 10, 'IsIndex': False}, {'value': Ref(id=1, collection=Ref(id=keys)), 'IsIndex': False}, {'value': Query({'api_version': '4', 'lambda': 'x', 'expr': {'var': 'x'}}), 'IsIndex': False}, {'value': None, 'IsIndex': False}, {'value': {'x': 10}, 'IsIndex': False}, {'value': Ref(id=employees, collection=Ref(id=roles)), 'IsIndex': False}, {'value': SetRef({'match': Ref(id=letters, collection=Ref(id=indexes))}), 'IsIndex': False}, {'value': 'ten', 'IsIndex': False}, {'value': '10', 'IsIndex': False}, {'value': FaunaTime('2020-07-06T12:34:56.789Z'), 'IsIndex': False}, {'value': Ref(id=1, collection=Ref(id=tokens)), 'IsIndex': False}]

result, err := client.Query(
	f.Map(
		f.Arr{
			f.Arr{"array"},
			true,
			false,
			f.BytesV{0x01, 0x02, 0x03, 0x04},
			f.Arr{0x1, 0x2, 0x3, 0x4},
			f.Collection("Letters"),
			f.Ref("credentials/self"),
			f.Database("child_db"),
			f.Date("2019-11-12"),
			f.Ref(f.Collection("Letters"), 123),
			10.1,
			f.Function("double"),
			f.Index("letters"),
			10,
			f.Ref(f.Keys(), "1"),
			f.Query(f.Lambda("x", f.Var("x"))),
			nil,
			f.Null(),
			f.Obj{"x": 10},
			f.Role("employees"),
			f.Match(f.Index("letters")),
			"ten",
			"10",
			f.Time("2020-07-06T12:34:56.789Z"),
			f.Ref(f.Tokens(), "1"),
		},
		f.Lambda("x", f.Obj{
			"value": f.Var("x"),
			"IsIndex": f.IsIndex(f.Var("x")),
		})))

if err != nil {
	fmt.Fprintln(os.Stderr, err)
} else {
	fmt.Println(result)
}

[map[IsIndex:false value:[array]] map[IsIndex:false value:true] map[IsIndex:false value:false] map[IsIndex:false value:[1 2 3 4]] map[IsIndex:false value:[1 2 3 4]] map[IsIndex:false value:{Letters 0xc0000b7e30 0xc0000b7e30 <nil>}] map[IsIndex:false value:{280481857410171392 0xc0000b7f50 0xc0000b7f50 <nil>}] map[IsIndex:false value:{child_db 0xc00015c090 0xc00015c090 <nil>}] map[IsIndex:false value:{0 63709113600 <nil>}] map[IsIndex:false value:{123 0xc000174150 0xc000174150 <nil>}] map[IsIndex:false value:10.1] map[IsIndex:false value:{double 0xc0001742a0 0xc0001742a0 <nil>}] map[IsIndex:true value:{letters 0xc0001743c0 0xc0001743c0 <nil>}] map[IsIndex:false value:10] map[IsIndex:false value:{1 0xc000174510 0xc000174510 <nil>}] map[IsIndex:false value:{[123 34 97 112 105 95 118 101 114 115 105 111 110 34 58 34 51 34 44 34 108 97 109 98 100 97 34 58 34 120 34 44 34 101 120 112 114 34 58 123 34 118 97 114 34 58 34 120 34 125 125]}] map[IsIndex:false value:{}] map[IsIndex:false value:{}] map[IsIndex:false value:map[x:10]] map[IsIndex:false value:{employees 0xc000174720 0xc000174720 <nil>}] map[IsIndex:false value:{map[match:{letters 0xc000174870 0xc000174870 <nil>}]}] map[IsIndex:false value:ten] map[IsIndex:false value:10] map[IsIndex:false value:{789000000 63729635696 <nil>}] map[IsIndex:false value:{1 0xc000174a20 0xc000174a20 <nil>}]]

try
{
    Value result = await client.Query(
        Map(
            Arr(
                Arr("array"),
                true,
                false,
                BytesV.Of(0x1, 0x2, 0x3, 0x4),
                Arr(0x1, 0x2, 0x3, 0x4),
                Collection("Letters"),
                Ref("credentials/self"),
                Database("child_db"),
                Date("2019-11-12"),
                Ref(Collection("Letters"), 123),
                10.1,
                Function("double"),
                Index("letters"),
                10,
                Ref(Keys(), "1"),
                Query(Lambda("x", Var("x"))),
                null,
                Obj("x", 10),
                Role("employees"),
                Match(Index("letters")),
                "ten",
                "10",
                Time("2020-07-06T12:34:56.789Z"),
                Ref(Tokens(), "1")
            ),
            Lambda(
                "x",
                Obj(
                    "value", Var("x"),
                    "IsIndex", IsIndex(Var("x"))
                )
            )
        )
    );

    Console.WriteLine(result);
}
catch (Exception e)
{
    Console.WriteLine($"ERROR: {e.Message}");
}

Arr(ObjectV(value: Arr(StringV(array)),IsIndex: BooleanV(False)), ObjectV(value: BooleanV(True),IsIndex: BooleanV(False)), ObjectV(value: BooleanV(False),IsIndex: BooleanV(False)), ObjectV(value: BytesV(0x01, 0x02, 0x03, 0x04),IsIndex: BooleanV(False)), ObjectV(value: Arr(LongV(1), LongV(2), LongV(3), LongV(4)),IsIndex: BooleanV(False)), ObjectV(value: RefV(id = "Letters", collection = RefV(id = "collections")),IsIndex: BooleanV(False)), ObjectV(value: RefV(id = "295433010882281984", collection = RefV(id = "credentials")),IsIndex: BooleanV(False)), ObjectV(value: RefV(id = "child_db", collection = RefV(id = "databases")),IsIndex: BooleanV(False)), ObjectV(value: FaunaDate(2019-11-12 12:00:00 AM),IsIndex: BooleanV(False)), ObjectV(value: RefV(id = "123", collection = RefV(id = "Letters", collection = RefV(id = "collections"))),IsIndex: BooleanV(False)), ObjectV(value: DoubleV(10.1),IsIndex: BooleanV(False)), ObjectV(value: RefV(id = "double", collection = RefV(id = "functions")),IsIndex: BooleanV(False)), ObjectV(value: RefV(id = "letters", collection = RefV(id = "indexes")),IsIndex: BooleanV(True)), ObjectV(value: LongV(10),IsIndex: BooleanV(False)), ObjectV(value: RefV(id = "1", collection = RefV(id = "keys")),IsIndex: BooleanV(False)), ObjectV(value: QueryV(System.Collections.Generic.Dictionary`2[System.String,FaunaDB.Query.Expr]),IsIndex: BooleanV(False)), ObjectV(value: NullV,IsIndex: BooleanV(False)), ObjectV(value: ObjectV(x: LongV(10)),IsIndex: BooleanV(False)), ObjectV(value: RefV(id = "employees", collection = RefV(id = "roles")),IsIndex: BooleanV(False)), ObjectV(value: SetRefV(System.Collections.Generic.Dictionary`2[System.String,FaunaDB.Types.Value]),IsIndex: BooleanV(False)), ObjectV(value: StringV(ten),IsIndex: BooleanV(False)), ObjectV(value: StringV(10),IsIndex: BooleanV(False)), ObjectV(value: FaunaTime(2020-07-06T12:34:56.789Z),IsIndex: BooleanV(False)), ObjectV(value: RefV(id = "1", collection = RefV(id = "tokens")),IsIndex: BooleanV(False)))

Map(
  [
    ['array'],
    true,
    false,
    new Uint8Array([1, 2, 3, 4]),
    [0x1, 0x2, 0x3, 0x4],
    Collection('Letters'),
    Ref('credentials/self'),
    Database('child_db'),
    Date('2019-11-12'),
    Ref(Collection('Letters'), 123),
    10.1,
    Function('double'),
    Index('letters'),
    10,
    Ref(Keys(), '1'),
    Query(Lambda('x', Var('x'))),
    null,
    { x: 10 },
    Role('employees'),
    Match(Index('letters')),
    'ten',
    '10',
    Time('2020-07-06T12:34:56.789Z'),
    Ref(Tokens(), '1'),
  ],
  Lambda('x', {
    value: Var('x'),
    IsIndex: IsIndex(Var('x')),
  })
)

[
  { value: [ 'array' ], IsIndex: false },
  { value: true, IsIndex: false },
  { value: false, IsIndex: false },
  { value: { '0': 1, '1': 2, '2': 3, '3': 4 }, IsIndex: false },
  { value: [ 1, 2, 3, 4 ], IsIndex: false },
  { value: Collection("Letters"), IsIndex: false },
  { value: Ref(Credentials(), "302043979982045696"), IsIndex: false },
  { value: Database("child_db"), IsIndex: false },
  { value: Date("2019-11-12"), IsIndex: false },
  { value: Ref(Collection("Letters"), "123"), IsIndex: false },
  { value: 10.1, IsIndex: false },
  { value: Function("double"), IsIndex: false },
  { value: Index("letters"), IsIndex: true },
  { value: 10, IsIndex: false },
  { value: Ref(Keys(), "1"), IsIndex: false },
  { value: Query(Lambda("x", Var("x"))), IsIndex: false },
  { value: null, IsIndex: false },
  { value: { x: 10 }, IsIndex: false },
  { value: Role("employees"), IsIndex: false },
  { value: Match(Index("letters")), IsIndex: false },
  { value: 'ten', IsIndex: false },
  { value: '10', IsIndex: false },
  { value: Time("2020-07-06T12:34:56.789Z"), IsIndex: false },
  { value: Ref(Tokens(), "1"), IsIndex: false }
]

Query metrics:

bytesIn: 598
bytesOut: 1,559
computeOps: 2
readOps: 0
writeOps: 0
readBytes: 373
writeBytes: 0
queryTime: 21ms
retries: 0

This query operates on a pre-existing schema, which is not provided here.

Also, the query is executed via a client connection, that uses a secret acquired by calling the Login function (not shown here), so that Ref("credentials/self") returns a valid value.

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IsIndex

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Returns

Examples

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`IsIndex`