Aggregation Expression - $dateToString

Function Build

Build $dateToString with the DateToString function from the aggregation package.

// bson.D{bson.E{Key:"dateText", Value:bson.D{bson.E{Key:"$dateToString", Value:bson.D{bson.E{Key:"date", Value:"$created_at"}, bson.E{Key:"format", Value:"%Y-%m-%d"}}}}}}
result := aggregation.DateToString("dateText", "$created_at", &aggregation.DateToStringOptions{Format: "%Y-%m-%d"})

Method Build (Builder)

Build $dateToString with the DateToString method from aggregation.NewBuilder().

// bson.D{bson.E{Key:"dateText", Value:bson.D{bson.E{Key:"$dateToString", Value:bson.D{bson.E{Key:"date", Value:"$created_at"}, bson.E{Key:"format", Value:"%Y-%m-%d"}}}}}}
result := aggregation.NewBuilder().
    DateToString("dateText", "$created_at", &aggregation.DateToStringOptions{Format: "%Y-%m-%d"}).
    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.

DateToStringWithoutKey

Function build:

// bson.D{bson.E{Key:"$dateToString", Value:bson.D{bson.E{Key:"date", Value:"$created_at"}, bson.E{Key:"format", Value:"%Y-%m-%d"}}}}
expr := aggregation.DateToStringWithoutKey("$created_at", &aggregation.DateToStringOptions{Format: "%Y-%m-%d"})

Method build (Builder):

// bson.D{bson.E{Key:"$dateToString", Value:bson.D{bson.E{Key:"date", Value:"$created_at"}, bson.E{Key:"format", Value:"%Y-%m-%d"}}}}
expr := aggregation.NewBuilder().
    DateToStringWithoutKey("$created_at", &aggregation.DateToStringOptions{Format: "%Y-%m-%d"}).
    Build()