refactor(npm): Extract two constants

Add documentation without polluting the function body with it.

Signed-off-by: Frank Viernau <[email protected]>

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

@@ -633,20 +633,24 @@ private fun nodeModulesDirForPackageJson(packageJson: File): File? {
     return modulesDir.takeIf { it.name == "node_modules" }
 }
 
+// Prefixes of std.err lines which can be ignored.
+private val IGNORABLE_LINE_PREFIXES = setOf(
+    "code ",
+    "deprecated ",
+    "errno ",
+    "path ",
+    "skipping integrity check for git dependency ",
+    "syscall "
+)
+
+// Prefixes of std.err lines which imply that a line with that prefix is not a multi-line output.
+private val SINGLE_LINE_PREFIXES = emptySet<String>()
+
 private fun List<String>.groupLines(marker: String): List<String> {
-    val ignorableLinePrefixes = setOf(
-        "code ",
-        "deprecated ",
-        "errno ",
-        "path ",
-        "skipping integrity check for git dependency ",
-        "syscall "
-    )
-    val singleLinePrefixes = emptySet<String>()
     val minCommonPrefixLength = 5
 
     val issueLines = mapNotNull { line ->
-        line.withoutPrefix(marker)?.takeUnless { ignorableLinePrefixes.any { prefix -> it.startsWith(prefix) } }
+        line.withoutPrefix(marker)?.takeUnless { IGNORABLE_LINE_PREFIXES.any { prefix -> it.startsWith(prefix) } }
     }
 
     var commonPrefix: String
@@ -668,7 +672,7 @@ private fun List<String>.groupLines(marker: String): List<String> {
                 }
             }
 
-            if (commonPrefix !in singleLinePrefixes && commonPrefix.length >= minCommonPrefixLength) {
+            if (commonPrefix !in SINGLE_LINE_PREFIXES && commonPrefix.length >= minCommonPrefixLength) {
                 // Do not drop the whole prefix but keep the space when concatenating lines.
                 messages[messages.size - 1] += line.drop(commonPrefix.length - 1).trimEnd()
                 previousPrefix = commonPrefix