feat(node): Tolerate authors with only an email address

Try to reconstruct the mandatory name from the email address via some
simple heuristic. This allows to parse packages like [1].

[1]: https://github.com/rehookify/datepicker/blob/a23eebcc7a2a1595fa72b4725073faae325ac446/package.json#L36

Signed-off-by: Sebastian Schuberth <sebastian@doubleopen.org>

Author: sschuberth

plugins/package-managers/node/src/main/kotlin/PackageJson.kt

@@ -186,10 +186,20 @@ private object AuthorListSerializer : JsonTransformingSerializer<List<Author>>(s
             is JsonObject -> listOf(this)
 
             is JsonPrimitive -> {
-                parseAuthorString(contentOrNull)
-                    .filter { it.name != null }
-                    .map { Author(checkNotNull(it.name), it.email, it.homepage) }
-                    .map { JSON.encodeToJsonElement(it) }
+                parseAuthorString(contentOrNull).mapNotNull { info ->
+                    when {
+                        info.name != null -> Author(checkNotNull(info.name), info.email, info.homepage)
+                        info.email == null -> null
+                        else -> {
+                            val nameFromEmail = checkNotNull(info.email).substringBefore('@')
+                                .replace('.', ' ')
+                                .replace(Regex("\\b([a-z])")) { it.value.uppercase() }
+                            Author(nameFromEmail, info.email, info.homepage)
+                        }
+                    }
+                }.map {
+                    JSON.encodeToJsonElement(it)
+                }
             }
 
             else -> throw SerializationException("Unexpected JSON element.")

plugins/package-managers/node/src/test/kotlin/PackageJsonTest.kt

@@ -29,7 +29,7 @@ import org.ossreviewtoolkit.plugins.packagemanagers.node.PackageJson.Author
 
 class PackageJsonTest : WordSpec({
     "parsePackageJson()" should {
-        "deserialize the author from a textual node" {
+        "deserialize the author from a primitive node with name and email" {
             val json = """
             {
               "author": "Jane Doe <jane.doe@example.com>"
@@ -43,6 +43,20 @@ class PackageJsonTest : WordSpec({
             )
         }
 
+        "deserialize the author from a primitive node with email only" {
+            val json = """
+            {
+              "author": "<jane.doe@example.com>"
+            }
+            """.trimIndent()
+
+            val packageJson = parsePackageJson(json)
+
+            packageJson.authors should containExactlyInAnyOrder(
+                Author(name = "Jane Doe", email = "jane.doe@example.com")
+            )
+        }
+
         "deserialize the author from an object node" {
             val json = """
             {