build.sbt - iteration over sub projects for common settings in monorepo - scala

Question

I'm implementing a monorepo using SBT. I would like to iterate over my subprojects in order to initialize them (as the have the same configuration) and prevent code duplication.
In my build.sbt:
lazy val root = (project in file("."))
.aggregate(projects: _*)
.settings(
crossScalaVersions := Nil,
publish / skip := true
)
lazy val projects = Seq("projectA", "projectB", "projectC")
.map((projectName: String) => (project in file(projectName))
.settings(
name := projectName,
commonSettings,
libraryDependencies ++= ModulesDependencies.get(projectName))
.project
)
I'm getting the error:
error: project must be directly assigned to a val, such as `val x = project`. Alternatively, you can use `sbt.Project.apply`
Based on the error message, I also tried to use sbt.Project.apply(projectName, file(projectName)).settings(...) instead, but I'm also facing some funny errors.
From what I understand, it seems that SBT expects me to declare as lazy val projectA = (project in file("projectA")).settings(...), which works fine but I would have to duplicate this code for all my sub projects.
Is this iteration that I try to implement even possible?

Answer 1

Utility method might help with some of the duplication, for example
def createProject(projectName: String) = {
Project(projectName, file(projectName))
.settings(
name := projectName,
commonSettings,
libraryDependencies ++= ModulesDependencies.get(projectName)
)
}
lazy val projectA = createProject("projectA")
lazy val projectB = createProject("projectB")
lazy val projectC = createProject("projectC")
lazy val root = (project in file("."))
.aggregate(projectA, projectB, projectB)
.settings(
crossScalaVersions := Nil,
publish / skip := true
)