Aggregation Expression - $filter

Function Build

Build $filter with the Filter function from the aggregation package.

// bson.D{bson.E{Key:"validScores", Value:bson.D{bson.E{Key:"$filter", Value:bson.D{bson.E{Key:"input", Value:"$scores"}, bson.E{Key:"cond", Value:bsonx.D("$gte", bson.A{"$$score", 60})}, bson.E{Key:"as", Value:"score"}}}}}}
result := aggregation.Filter("validScores", "$scores", bsonx.D("$gte", bson.A{"$$score", 60}), &aggregation.FilterOptions{As: "score"})

Method Build (Builder)

Build $filter with the Filter method from aggregation.NewBuilder().

// bson.D{bson.E{Key:"validScores", Value:bson.D{bson.E{Key:"$filter", Value:bson.D{bson.E{Key:"input", Value:"$scores"}, bson.E{Key:"cond", Value:bsonx.D("$gte", bson.A{"$$score", 60})}, bson.E{Key:"as", Value:"score"}}}}}}
result := aggregation.NewBuilder().
    Filter("validScores", "$scores", bsonx.D("$gte", bson.A{"$$score", 60}), &aggregation.FilterOptions{As: "score"}).
    Build()

Build Without Key

When an expression needs to be passed as an argument to another expression, use a WithoutKey variant to build an expression fragment without an output field name.

FilterWithoutKey

Function build:

// bson.D{bson.E{Key:"$filter", Value:bson.D{bson.E{Key:"input", Value:"$scores"}, bson.E{Key:"cond", Value:aggregation.GteWithoutKey("$$score", 60)}, bson.E{Key:"as", Value:"score"}}}}
expr := aggregation.FilterWithoutKey("$scores", aggregation.GteWithoutKey("$$score", 60), &aggregation.FilterOptions{As: "score"})

Method build (Builder):

// bson.D{bson.E{Key:"$filter", Value:bson.D{bson.E{Key:"input", Value:"$scores"}, bson.E{Key:"cond", Value:aggregation.GteWithoutKey("$$score", 60)}, bson.E{Key:"as", Value:"score"}}}}
expr := aggregation.NewBuilder().
    FilterWithoutKey("$scores", aggregation.GteWithoutKey("$$score", 60), &aggregation.FilterOptions{As: "score"}).
    Build()