IsSet
IsSet( value )Description
The IsSet function returns true only if value is a
Set, otherwise it returns false.
Parameters
| Argument | Type | Definition and Requirements |
|---|---|---|
|
Any |
Any value, which is to be tested to determine whether it is a set 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 IsSet
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('all_letters'),
10,
q.Ref(q.Keys(), '248967241620521472'),
q.Query(q.Lambda('x', q.Var('x'))),
null,
{ x: 10 },
q.Role('employees'),
q.Match(q.Index('all_letters')),
'ten',
'10',
q.Now(),
q.Ref(q.Tokens(), '249062079147803136'),
],
q.Lambda('x', {
value: q.Var('x'),
IsSet: q.IsSet(q.Var('x')),
})
)
)
.then((ret) => console.log(ret))[ { value: [ 'array' ], IsSet: false },
{ value: true, IsSet: false },
{ value: false, IsSet: false },
{ value: Bytes("AQIDBA=="), IsSet: false },
{ value: [ 1, 2, 3, 4 ], IsSet: false },
{ value: Collection("Letters"), IsSet: false },
{ value: Ref(Credentials(), "248967019900174848"),
IsSet: false },
{ value: Database("child_db"), IsSet: false },
{ value: Date("2019-11-12"), IsSet: false },
{ value: Ref(Collection("Letters"), "123"), IsSet: false },
{ value: 10.1, IsSet: false },
{ value: Function("double"), IsSet: false },
{ value: Index("all_letters"), IsSet: false },
{ value: 10, IsSet: false },
{ value: Ref(Keys(), "248967241620521472"), IsSet: false },
{ value: Query(Lambda("x", Var("x"))), IsSet: false },
{ value: null, IsSet: false },
{ value: { x: 10 }, IsSet: false },
{ value: Role("employees"), IsSet: false },
{ value: Match(Index("all_letters")), IsSet: true },
{ value: 'ten', IsSet: false },
{ value: '10', IsSet: false },
{ value: Time("2019-11-12T13:15:16.789Z"), IsSet: false },
{ value: Ref(Tokens(), "249062079147803136"), IsSet: false } ]|
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
|
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