Description
Returns documents from a fixed set of predefined document objects.
This stage is commonly used for testing other stages in isolation, though it can also be used as input to join conditions.
Syntax
Node.js
const
results
=
await
db
.
pipeline
()
.
literals
({
name
:
"joe"
,
age
:
10
},
{
name
:
"bob"
,
age
:
30
},
{
name
:
"alice"
,
age
:
40
})
.
where
(
field
(
"age"
).
lessThan
(
35
))
.
execute
();
...
[
{
name
:
"joe"
,
age
:
10
},
{
name
:
"bob"
,
age
:
30
}
]
Behavior
The literals(...)
stage can only be used as the first stage in a pipeline (or
sub-pipeline). The order of documents returned from the literals
matches the
order in which they are defined.
While literal values are the most common, it is also possible to pass in expressions, which will be evaluated and returned, making it possible to test out different query / expression behavior without first needing to create some test data.
For example, the following shows how to quickly test out the length(...)
function on some constant test sets:
Node.js
const
results
=
await
db
.
pipeline
()
.
literals
({
x
:
constant
(
"foo-bar-baz"
).
length
()
},
{
x
:
constant
(
"bar"
).
length
()
})
.
execute
();
...
[
{
x
:
11
},
{
x
:
3
}
]
