flatMap()
Description
The flatMap()
method creates an Set by invoking function on
each element of the calling set and flattening the
resulting set one level. The Set elements are passed as a
parameter to function, sequentially.
The calling set isn’t changed.
Parameters
Return value
Type | Description |
---|---|
Set of the result of calling function on each element of the calling set. The resulting set is flattened by one level. |
Examples
The following query uses map()
and returns a nested set.
// Returns a set
let topCustomer = Customer.byEmail("alice.appleseed@example.com")
// Returns a nested set
topCustomer.map((customer) => Order.byCustomer(customer))
{
data: [
{
data: [
{
id: "392698761120317504",
coll: Order,
ts: Time("2099-03-18T12:39:32.610Z"),
customer: Customer.byId("392698761099345984"),
...
}
]
}
]
}
The following query uses flatmap()
to flatten the returned set.
// Returns a set
let topCustomer = Customer.byEmail("alice.appleseed@example.com")
// Returns a flattened set
topCustomer.flatMap((customer) => Order.byCustomer(customer))
{
data: [
{
id: "392698761120317504",
coll: Order,
ts: Time("2099-03-18T12:39:32.610Z"),
customer: Customer.byId("392698761099345984"),
...
}
]
}
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