title: specifying mainClass for scala.js?
body: <p>I was doing this tutorial on scala.js in a project with two other main classes already: <a href="https://www.scala-js.org/doc/tutorial/basic/index.html" rel="nofollow noreferrer">https://www.scala-js.org/doc/tutorial/basic/index.html</a> </p>
  
  <p>In my build.sbt file, I had written this line of code.</p>
  
  <pre><code>scalaJSUseMainModuleInitializer := true
  </code></pre>
  
  <p>Then, I got this error:</p>
  
  <pre><code>[error] (Compile / scalaJSModuleInitializers) No main module initializer was specified (possibly because no or multiple main classes were found), but scalaJSUseMainModuleIni
  tializer was set to true. You can explicitly specify it either with `mainClass := Some(...)` or with `scalaJSMainModuleInitializer := Some(...)`
  </code></pre>
  
  <p>I'm trying to specify the main class, or to get it to compile using the second option (scalaJSMainModuleInitializer := Some(...)).</p>
  
  <p>The folder of the main class is in src/main/scala/scalaJSclasses/webapp, the main class is called App, and the main method is called main.</p>
  
  <p>what goes in the (...)??</p>
  
  <p>I've tried</p>
  
  <pre><code>mainClass := Some("src/main/scala/scalaJSclasses.webapp.App.main")
  mainClass := Some("src/main/scala/scalaJSclasses.webapp.App")
  
  
  </code></pre>
  
  <p>and</p>
  
  <pre><code>scalaJSUseMainModuleInitializer := mainMethod("scalaJSclasses.webapp.App.Main", "main")
  </code></pre>
  
  <p>I guess I just need help with figuring out how it read the path to the file. Please help.</p>