Foreach

Foreach( collection, lambda )
Foreach( collection, lambda )
Foreach( collection, lambda )
Foreach( collection, lambda )
foreach( lambda, collection )
foreach collection, lambda
Foreach( collection, lambda )
Foreach( collection, lambda )

Description

The Foreach function applies the Lambda serially to each member of an array, and returns the original array. The Foreach function is very useful when the original array does not need to be modified, but a side effect is required for every value in an array. Later invocations of the Lambda can see the side effects of earlier invocations of the Lambda.

Parameters

Argument Type Definition and Requirements

array

The target array over which the lambda function iterates/operates.

lambda

The anonymous function to be executed.

Returns

The original array without any modifications.

Examples

The query below iterates over the results returned by the Paginate function, executing the Lambda for each value in the result array. The result array contains an array of references, each reference’s document is updated by the lambda.

curl https://db.fauna.com/ \
    -u fnAChGwBcAACAO70ziE0cfROosNJHdgBmJU1PgpL: \
    -d '{
          "foreach": {
            "lambda": "spell",
            "expr": {
              "update": { "var": "spell" },
              "params": {
                "object": {
                  "data": {
                    "object": {
                      "spellbook": { "@ref": "classes/spellbooks/181388642139243008" }
                    }
                  }
                }
              }
            }
          },
          "class": {
            "paginate": {
              "match": { "index": "spells_by_element" },
              "terms": "fire"
            }
          }
        }'
client.Query(
  Foreach(
    Paginate(Match(Index("spells_by_element"), "fire")),
    spell => Update(
      spell,
      Obj(
        "data", Obj(
          "spellbook", Ref(Collection("spellbooks"), "181388642139243008")
        )
      ))));
System.out.println(
      client.query(
          Foreach(
             Paginate(
                Match(Index(Value("spells_by_element")), Value("fire"))
             ),
             Lambda(
                Value("spell"),
                Update(
                   Var("spell"),
                   Obj("data",
                      Obj("spellbook",
                      Ref(Collection(Value("spellbooks")),Value(181388642139243008L)))
                   )
                )
             )
         )
      ).get()
);
result, _ := client.Query(
    f.Foreach(
        f.Paginate(
            f.MatchTerm(f.Index("spells_by_element"), "fire"),
        ),
        f.Lambda(
            "spell",
            f.Update(
                f.Var("spell"),
                f.Obj{
                    "data": f.Obj{
                        "spellbook": f.RefCollection(f.Collection("spellbooks"), "181388642139243008"),
                    },
                },
            ),
        ),
    ),
)

fmt.Println(result)
client.query(
  Foreach(
    Paginate(Match(Index("spells_by_element"), "fire")),
    Lambda { spell =>
      Update(
        spell,
        Obj(
          "data" -> Obj(
            "spellbook" -> Ref(Collection("spellbooks"), "181388642139243008")
          )
        ))
    }))
client.query(
  q.foreach(
    lambda spell: q.update(
      spell,
      {
        "data": {
          "spellbook": q.ref(q.collection("spellbooks"), "181388642139243008")
        }
      }
    ),
    q.paginate(q.match(q.index("spells_by_element"), "fire"))
  ))
$client.query do
  foreach paginate(match(index('spells_by_element'), 'fire')) do |spell|
    update(spell,
           data: { spellbook: ref(collection('spellbooks'), '181388642139243008') })
  end
end
client.query(
    Foreach(
        collection: Paginate(
            Match(
                index: Index("spells_by_element"),
                terms: "fire"
            )
        ),
        in: { spell in
            Update(
                ref: spell,
                to: Obj(
                    "data" => Obj(
                        "spellbook" => Ref(Collection("spellbooks"), "181388642139243008")
                    )
                )
            )
        }
    )
)
client.query(
  q.Foreach(
    q.Paginate(
      q.Match(q.Index("spells_by_element"), "fire")
    ),
    q.Lambda("spell",
      q.Update(
        q.Var("spell"), {
          data: {
            spellbook: q.Ref(
              q.Collection("spellbooks"),
              "181388642139243008"
            )
          }
        }
      )
    )
  )
)
.then((ret) => console.log(ret));
HTTP/1.1 200 OK
{
  "resource": {
    "data": [
      { "@ref": "classes/spells/181388642046968320" },
      { "@ref": "classes/spells/181388642071085568" }
    ]
  }
}
{
  "data": [
    { "@ref": "classes/spells/181388642046968320" },
    { "@ref": "classes/spells/181388642071085568" }
  ]
}
{
  data: [
    ref(id = "181388642046968320", collection = ref(id = "spells", collection = ref(id = "collections"))),
    ref(id = "181388642071085568", collection = ref(id = "spells", collection = ref(id = "collections")))
  ]
}
map[data:[{181388642046968320 0xc4201c3720 <nil>} {181388642071085568 0xc4201c3940 <nil>}]]
{
  "data": [
    { "@ref": "classes/spells/181388642046968320" },
    { "@ref": "classes/spells/181388642071085568" }
  ]
}
{
  "data": [
    { "@ref": "classes/spells/181388642046968320" },
    { "@ref": "classes/spells/181388642071085568" }
  ]
}
{
  "data": [
    { "@ref": "classes/spells/181388642046968320" },
    { "@ref": "classes/spells/181388642071085568" }
  ]
}
{
  "data": [
    { "@ref": "classes/spells/181388642046968320" },
    { "@ref": "classes/spells/181388642071085568" }
  ]
}
{ data:
   [ Ref(id=181388642046968320, collection=Ref(id=spells, collection=Ref(id=collections))),
     Ref(id=181388642071085568, collection=Ref(id=spells, collection=Ref(id=collections))) ] }

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