diff --git a/lib-extra/build.gradle b/lib-extra/build.gradle
index 95eef4046c..45a754cded 100644
--- a/lib-extra/build.gradle
+++ b/lib-extra/build.gradle
@@ -23,7 +23,3 @@ dependencies {
 
 // we'll hold the core lib to a high standard
 spotbugs { reportLevel = 'low' } // low|medium|high (low = sensitive to even minor mistakes)
-
-test { useJUnit { excludeCategories 'com.diffplug.spotless.category.NpmTest' } }
-
-task npmTest(type: Test) { useJUnit { includeCategories 'com.diffplug.spotless.category.NpmTest' } }
diff --git a/lib/build.gradle b/lib/build.gradle
index 16eb81f30b..79b7fce713 100644
--- a/lib/build.gradle
+++ b/lib/build.gradle
@@ -13,3 +13,7 @@ dependencies {
 
 // we'll hold the core lib to a high standard
 spotbugs { reportLevel = 'low' } // low|medium|high (low = sensitive to even minor mistakes)
+
+test { useJUnit { excludeCategories 'com.diffplug.spotless.category.NpmTest' } }
+
+task npmTest(type: Test) { useJUnit { includeCategories 'com.diffplug.spotless.category.NpmTest' } }
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/BlacklistedOptionException.java b/lib/src/main/java/com/diffplug/spotless/npm/BlacklistedOptionException.java
similarity index 95%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/BlacklistedOptionException.java
rename to lib/src/main/java/com/diffplug/spotless/npm/BlacklistedOptionException.java
index f82751274d..3704f487dc 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/BlacklistedOptionException.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/BlacklistedOptionException.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 class BlacklistedOptionException extends RuntimeException {
 	private static final long serialVersionUID = -5876348893394153811L;
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/NodeJSWrapper.java b/lib/src/main/java/com/diffplug/spotless/npm/NodeJSWrapper.java
similarity index 98%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/NodeJSWrapper.java
rename to lib/src/main/java/com/diffplug/spotless/npm/NodeJSWrapper.java
index 407865680f..1ae4efd199 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/NodeJSWrapper.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/NodeJSWrapper.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import java.io.File;
 import java.util.Map;
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/NpmConfig.java b/lib/src/main/java/com/diffplug/spotless/npm/NpmConfig.java
similarity index 96%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/NpmConfig.java
rename to lib/src/main/java/com/diffplug/spotless/npm/NpmConfig.java
index 768f995af5..55d3683606 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/NpmConfig.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/NpmConfig.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import java.io.Serializable;
 
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/NpmExecutableResolver.java b/lib/src/main/java/com/diffplug/spotless/npm/NpmExecutableResolver.java
similarity index 91%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/NpmExecutableResolver.java
rename to lib/src/main/java/com/diffplug/spotless/npm/NpmExecutableResolver.java
index 760f704727..cbbf6bc6bd 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/NpmExecutableResolver.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/NpmExecutableResolver.java
@@ -13,17 +13,16 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
-import static com.diffplug.spotless.extra.npm.PlatformInfo.OS.WINDOWS;
+import static com.diffplug.spotless.npm.PlatformInfo.OS.WINDOWS;
 
 import java.io.File;
+import java.util.Arrays;
 import java.util.Optional;
 import java.util.function.Supplier;
 import java.util.stream.Stream;
 
-import com.diffplug.common.base.Splitter;
-
 /**
  * Utility class to resolve an npm binary to be used by npm-based steps.
  * Tries to find an npm executable in the following order:
@@ -84,9 +83,7 @@ private static Supplier<Optional<File>> pathListFromEnvironment(String environme
 		return () -> {
 			String pathList = System.getenv(environmentPathListName);
 			if (pathList != null) {
-				return Splitter.on(System.getProperty("path.separator", ":"))
-						.splitToList(pathList)
-						.stream()
+				return Arrays.stream(pathList.split(System.getProperty("path.separator", ":")))
 						.map(File::new)
 						.map(dir -> dir.getName().equalsIgnoreCase("node_modules") ? dir.getParentFile() : dir)
 						.map(dir -> new File(dir, npmExecutableName()))
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/NpmFormatterStepStateBase.java b/lib/src/main/java/com/diffplug/spotless/npm/NpmFormatterStepStateBase.java
similarity index 91%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/NpmFormatterStepStateBase.java
rename to lib/src/main/java/com/diffplug/spotless/npm/NpmFormatterStepStateBase.java
index 94f7e68222..1fc056fa0d 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/NpmFormatterStepStateBase.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/NpmFormatterStepStateBase.java
@@ -13,9 +13,8 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
-import static com.diffplug.spotless.extra.npm.NpmExecutableResolver.tryFind;
 import static java.util.Objects.requireNonNull;
 
 import java.io.ByteArrayOutputStream;
@@ -29,11 +28,7 @@
 
 import javax.annotation.Nullable;
 
-import com.diffplug.common.base.Errors;
-import com.diffplug.spotless.FileSignature;
-import com.diffplug.spotless.FormatterFunc;
-import com.diffplug.spotless.JarState;
-import com.diffplug.spotless.Provisioner;
+import com.diffplug.spotless.*;
 
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 
@@ -92,7 +87,7 @@ private void runNpmInstall(@Nullable File npm, File npmProjectDir) throws IOExce
 
 	private File resolveNpm(@Nullable File npm) {
 		return Optional.ofNullable(npm)
-				.orElseGet(() -> tryFind()
+				.orElseGet(() -> NpmExecutableResolver.tryFind()
 						.orElseThrow(() -> new IllegalStateException("cannot automatically determine npm executable and none was specifically supplied!")));
 	}
 
@@ -118,7 +113,7 @@ protected static String readFileFromClasspath(Class<?> clazz, String name) {
 			}
 			return output.toString(StandardCharsets.UTF_8.name());
 		} catch (IOException e) {
-			throw Errors.asRuntime(e);
+			throw ThrowingEx.asRuntime(e);
 		}
 	}
 
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/PlatformInfo.java b/lib/src/main/java/com/diffplug/spotless/npm/PlatformInfo.java
similarity index 90%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/PlatformInfo.java
rename to lib/src/main/java/com/diffplug/spotless/npm/PlatformInfo.java
index de49ca5f31..2065b0ca54 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/PlatformInfo.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/PlatformInfo.java
@@ -13,21 +13,19 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import static java.util.Objects.requireNonNull;
 
 import java.util.Locale;
 
-import com.diffplug.common.base.StandardSystemProperty;
-
 class PlatformInfo {
 	private PlatformInfo() {
 		// no instance
 	}
 
 	static OS normalizedOS() {
-		final String osNameProperty = StandardSystemProperty.OS_NAME.value();
+		final String osNameProperty = System.getProperty("os.name");
 		if (osNameProperty == null) {
 			throw new RuntimeException("No info about OS available, cannot decide which implementation of j2v8 to use");
 		}
@@ -49,7 +47,7 @@ static String normalizedOSName() {
 	}
 
 	static String normalizedArchName() {
-		final String osArchProperty = StandardSystemProperty.OS_ARCH.value();
+		final String osArchProperty = System.getProperty("os.arch");
 		if (osArchProperty == null) {
 			throw new RuntimeException("No info about ARCH available, cannot decide which implementation of j2v8 to use");
 		}
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/PrettierConfig.java b/lib/src/main/java/com/diffplug/spotless/npm/PrettierConfig.java
similarity index 97%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/PrettierConfig.java
rename to lib/src/main/java/com/diffplug/spotless/npm/PrettierConfig.java
index 214eec5d67..328cb25a4e 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/PrettierConfig.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/PrettierConfig.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import java.io.File;
 import java.io.IOException;
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/PrettierFormatterStep.java b/lib/src/main/java/com/diffplug/spotless/npm/PrettierFormatterStep.java
similarity index 98%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/PrettierFormatterStep.java
rename to lib/src/main/java/com/diffplug/spotless/npm/PrettierFormatterStep.java
index 4aaa23cd08..56842ef413 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/PrettierFormatterStep.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/PrettierFormatterStep.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import static java.util.Arrays.asList;
 import static java.util.Objects.requireNonNull;
@@ -53,7 +53,7 @@ public static class State extends NpmFormatterStepStateBase implements Serializa
 			super(stepName,
 					provisioner,
 					new NpmConfig(
-							readFileFromClasspath(PrettierFormatterStep.class, "/com/diffplug/spotless/extra/npm/prettier-package.json"),
+							readFileFromClasspath(PrettierFormatterStep.class, "/com/diffplug/spotless/npm/prettier-package.json"),
 							"prettier"),
 					buildDir,
 					npm);
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/Reflective.java b/lib/src/main/java/com/diffplug/spotless/npm/Reflective.java
similarity index 99%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/Reflective.java
rename to lib/src/main/java/com/diffplug/spotless/npm/Reflective.java
index c68fe43fb0..5f68606fa7 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/Reflective.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/Reflective.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import static java.util.Objects.requireNonNull;
 
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/ReflectiveObjectWrapper.java b/lib/src/main/java/com/diffplug/spotless/npm/ReflectiveObjectWrapper.java
similarity index 98%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/ReflectiveObjectWrapper.java
rename to lib/src/main/java/com/diffplug/spotless/npm/ReflectiveObjectWrapper.java
index e10b23a366..3dfffc8c94 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/ReflectiveObjectWrapper.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/ReflectiveObjectWrapper.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import static java.util.Objects.requireNonNull;
 
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/SimpleJsonWriter.java b/lib/src/main/java/com/diffplug/spotless/npm/SimpleJsonWriter.java
similarity index 95%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/SimpleJsonWriter.java
rename to lib/src/main/java/com/diffplug/spotless/npm/SimpleJsonWriter.java
index 9f786cf484..8650f086c4 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/SimpleJsonWriter.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/SimpleJsonWriter.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import static java.util.Objects.requireNonNull;
 
@@ -26,7 +26,7 @@
 import java.util.Map;
 import java.util.stream.Collectors;
 
-import com.diffplug.common.base.Errors;
+import com.diffplug.spotless.ThrowingEx;
 
 public class SimpleJsonWriter {
 
@@ -83,7 +83,7 @@ void toJsonFile(File file) {
 		try {
 			Files.write(file.toPath(), toJsonString().getBytes(StandardCharsets.UTF_8));
 		} catch (IOException e) {
-			throw Errors.asRuntime(e);
+			throw ThrowingEx.asRuntime(e);
 		}
 	}
 
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/TsConfigFileType.java b/lib/src/main/java/com/diffplug/spotless/npm/TsConfigFileType.java
similarity index 96%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/TsConfigFileType.java
rename to lib/src/main/java/com/diffplug/spotless/npm/TsConfigFileType.java
index 5e118ad81e..19251f7a76 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/TsConfigFileType.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/TsConfigFileType.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import java.util.Arrays;
 
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/TsFmtFormatterStep.java b/lib/src/main/java/com/diffplug/spotless/npm/TsFmtFormatterStep.java
similarity index 98%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/TsFmtFormatterStep.java
rename to lib/src/main/java/com/diffplug/spotless/npm/TsFmtFormatterStep.java
index 320c638b08..52d7a31d2b 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/TsFmtFormatterStep.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/TsFmtFormatterStep.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import static java.util.Arrays.asList;
 import static java.util.Objects.requireNonNull;
@@ -61,7 +61,7 @@ public State(String stepName, Provisioner provisioner, File buildDir, @Nullable
 			super(stepName,
 					provisioner,
 					new NpmConfig(
-							readFileFromClasspath(TsFmtFormatterStep.class, "/com/diffplug/spotless/extra/npm/tsfmt-package.json"),
+							readFileFromClasspath(TsFmtFormatterStep.class, "/com/diffplug/spotless/npm/tsfmt-package.json"),
 							"typescript-formatter"),
 					buildDir,
 					npm);
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/TsFmtResult.java b/lib/src/main/java/com/diffplug/spotless/npm/TsFmtResult.java
similarity index 96%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/TsFmtResult.java
rename to lib/src/main/java/com/diffplug/spotless/npm/TsFmtResult.java
index 7ca8418a17..c43f4963f3 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/TsFmtResult.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/TsFmtResult.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 class TsFmtResult {
 
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/TypedTsFmtConfigFile.java b/lib/src/main/java/com/diffplug/spotless/npm/TypedTsFmtConfigFile.java
similarity index 94%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/TypedTsFmtConfigFile.java
rename to lib/src/main/java/com/diffplug/spotless/npm/TypedTsFmtConfigFile.java
index 003dee524f..9968c5c068 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/TypedTsFmtConfigFile.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/TypedTsFmtConfigFile.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import static java.util.Objects.requireNonNull;
 
@@ -22,8 +22,8 @@
 import java.io.Serializable;
 import java.util.Locale;
 
-import com.diffplug.common.base.Errors;
 import com.diffplug.spotless.FileSignature;
+import com.diffplug.spotless.ThrowingEx;
 
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 
@@ -45,7 +45,7 @@ public TypedTsFmtConfigFile(TsConfigFileType configFileType, File configFile) {
 		try {
 			this.configFileSignature = FileSignature.signAsList(configFile);
 		} catch (IOException e) {
-			throw Errors.asRuntime(e);
+			throw ThrowingEx.asRuntime(e);
 		}
 	}
 
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/V8ArrayWrapper.java b/lib/src/main/java/com/diffplug/spotless/npm/V8ArrayWrapper.java
similarity index 84%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/V8ArrayWrapper.java
rename to lib/src/main/java/com/diffplug/spotless/npm/V8ArrayWrapper.java
index 7dba2f354b..0d26df0b64 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/V8ArrayWrapper.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/V8ArrayWrapper.java
@@ -13,9 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
-
-import static com.diffplug.spotless.extra.npm.NodeJSWrapper.V8_VALUE_CLASS;
+package com.diffplug.spotless.npm;
 
 public class V8ArrayWrapper extends ReflectiveObjectWrapper {
 
@@ -30,8 +28,8 @@ public V8ArrayWrapper push(Object object) {
 			ReflectiveObjectWrapper objectWrapper = (ReflectiveObjectWrapper) object;
 			object = objectWrapper.wrappedObj();
 		}
-		if (reflective().clazz(V8_VALUE_CLASS).isAssignableFrom(object.getClass())) {
-			invoke("push", reflective().typed(V8_VALUE_CLASS, object));
+		if (reflective().clazz(NodeJSWrapper.V8_VALUE_CLASS).isAssignableFrom(object.getClass())) {
+			invoke("push", reflective().typed(NodeJSWrapper.V8_VALUE_CLASS, object));
 		} else {
 			invoke("push", object);
 		}
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/V8FunctionWrapper.java b/lib/src/main/java/com/diffplug/spotless/npm/V8FunctionWrapper.java
similarity index 98%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/V8FunctionWrapper.java
rename to lib/src/main/java/com/diffplug/spotless/npm/V8FunctionWrapper.java
index 9eefa13a61..36a9804854 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/V8FunctionWrapper.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/V8FunctionWrapper.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import java.lang.reflect.Method;
 
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/V8ObjectUtilsWrapper.java b/lib/src/main/java/com/diffplug/spotless/npm/V8ObjectUtilsWrapper.java
similarity index 96%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/V8ObjectUtilsWrapper.java
rename to lib/src/main/java/com/diffplug/spotless/npm/V8ObjectUtilsWrapper.java
index 0bd785795f..af7448c748 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/V8ObjectUtilsWrapper.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/V8ObjectUtilsWrapper.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import static java.util.Objects.requireNonNull;
 
diff --git a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/V8ObjectWrapper.java b/lib/src/main/java/com/diffplug/spotless/npm/V8ObjectWrapper.java
similarity index 98%
rename from lib-extra/src/main/java/com/diffplug/spotless/extra/npm/V8ObjectWrapper.java
rename to lib/src/main/java/com/diffplug/spotless/npm/V8ObjectWrapper.java
index ca5d69eaa1..917e25c222 100644
--- a/lib-extra/src/main/java/com/diffplug/spotless/extra/npm/V8ObjectWrapper.java
+++ b/lib/src/main/java/com/diffplug/spotless/npm/V8ObjectWrapper.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import java.util.Optional;
 
diff --git a/lib-extra/src/main/resources/com/diffplug/spotless/extra/npm/prettier-package.json b/lib/src/main/resources/com/diffplug/spotless/npm/prettier-package.json
similarity index 100%
rename from lib-extra/src/main/resources/com/diffplug/spotless/extra/npm/prettier-package.json
rename to lib/src/main/resources/com/diffplug/spotless/npm/prettier-package.json
diff --git a/lib-extra/src/main/resources/com/diffplug/spotless/extra/npm/tsfmt-package.json b/lib/src/main/resources/com/diffplug/spotless/npm/tsfmt-package.json
similarity index 100%
rename from lib-extra/src/main/resources/com/diffplug/spotless/extra/npm/tsfmt-package.json
rename to lib/src/main/resources/com/diffplug/spotless/npm/tsfmt-package.json
diff --git a/plugin-gradle/src/main/java/com/diffplug/gradle/spotless/FormatExtension.java b/plugin-gradle/src/main/java/com/diffplug/gradle/spotless/FormatExtension.java
index 1ab9bad52f..e19e88e356 100644
--- a/plugin-gradle/src/main/java/com/diffplug/gradle/spotless/FormatExtension.java
+++ b/plugin-gradle/src/main/java/com/diffplug/gradle/spotless/FormatExtension.java
@@ -35,13 +35,13 @@
 import com.diffplug.spotless.LazyForwardingEquality;
 import com.diffplug.spotless.LineEnding;
 import com.diffplug.spotless.ThrowingEx;
-import com.diffplug.spotless.extra.npm.PrettierFormatterStep;
 import com.diffplug.spotless.generic.EndWithNewlineStep;
 import com.diffplug.spotless.generic.IndentStep;
 import com.diffplug.spotless.generic.LicenseHeaderStep;
 import com.diffplug.spotless.generic.ReplaceRegexStep;
 import com.diffplug.spotless.generic.ReplaceStep;
 import com.diffplug.spotless.generic.TrimTrailingWhitespaceStep;
+import com.diffplug.spotless.npm.PrettierFormatterStep;
 
 import groovy.lang.Closure;
 
@@ -471,7 +471,7 @@ FormatterStep createStep() {
 					GradleProvisioner.fromProject(project),
 					project.getBuildDir(),
 					npmFileOrNull(),
-					new com.diffplug.spotless.extra.npm.PrettierConfig(
+					new com.diffplug.spotless.npm.PrettierConfig(
 							this.prettierConfigFile != null ? project.file(this.prettierConfigFile) : null,
 							this.prettierConfig));
 		}
diff --git a/plugin-gradle/src/main/java/com/diffplug/gradle/spotless/TypescriptExtension.java b/plugin-gradle/src/main/java/com/diffplug/gradle/spotless/TypescriptExtension.java
index 96cb7e788c..b20a4e34c1 100644
--- a/plugin-gradle/src/main/java/com/diffplug/gradle/spotless/TypescriptExtension.java
+++ b/plugin-gradle/src/main/java/com/diffplug/gradle/spotless/TypescriptExtension.java
@@ -26,9 +26,9 @@
 import org.gradle.api.Project;
 
 import com.diffplug.spotless.FormatterStep;
-import com.diffplug.spotless.extra.npm.TsConfigFileType;
-import com.diffplug.spotless.extra.npm.TsFmtFormatterStep;
-import com.diffplug.spotless.extra.npm.TypedTsFmtConfigFile;
+import com.diffplug.spotless.npm.TsConfigFileType;
+import com.diffplug.spotless.npm.TsFmtFormatterStep;
+import com.diffplug.spotless.npm.TypedTsFmtConfigFile;
 
 public class TypescriptExtension extends FormatExtension {
 
diff --git a/lib-extra/src/test/java/com/diffplug/spotless/extra/npm/NpmFormatterStepCommonTests.java b/testlib/src/test/java/com/diffplug/spotless/npm/NpmFormatterStepCommonTests.java
similarity index 96%
rename from lib-extra/src/test/java/com/diffplug/spotless/extra/npm/NpmFormatterStepCommonTests.java
rename to testlib/src/test/java/com/diffplug/spotless/npm/NpmFormatterStepCommonTests.java
index e519892c2a..79b58ab5a9 100644
--- a/lib-extra/src/test/java/com/diffplug/spotless/extra/npm/NpmFormatterStepCommonTests.java
+++ b/testlib/src/test/java/com/diffplug/spotless/npm/NpmFormatterStepCommonTests.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import java.io.File;
 import java.io.IOException;
diff --git a/lib-extra/src/test/java/com/diffplug/spotless/extra/npm/PrettierFormatterStepTest.java b/testlib/src/test/java/com/diffplug/spotless/npm/PrettierFormatterStepTest.java
similarity index 99%
rename from lib-extra/src/test/java/com/diffplug/spotless/extra/npm/PrettierFormatterStepTest.java
rename to testlib/src/test/java/com/diffplug/spotless/npm/PrettierFormatterStepTest.java
index 0f9440ac3b..508a49a28a 100644
--- a/lib-extra/src/test/java/com/diffplug/spotless/extra/npm/PrettierFormatterStepTest.java
+++ b/testlib/src/test/java/com/diffplug/spotless/npm/PrettierFormatterStepTest.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import java.io.File;
 import java.util.Arrays;
diff --git a/lib-extra/src/test/java/com/diffplug/spotless/extra/npm/SimpleJsonWriterTest.java b/testlib/src/test/java/com/diffplug/spotless/npm/SimpleJsonWriterTest.java
similarity index 98%
rename from lib-extra/src/test/java/com/diffplug/spotless/extra/npm/SimpleJsonWriterTest.java
rename to testlib/src/test/java/com/diffplug/spotless/npm/SimpleJsonWriterTest.java
index 69e13e2531..787bba49ff 100644
--- a/lib-extra/src/test/java/com/diffplug/spotless/extra/npm/SimpleJsonWriterTest.java
+++ b/testlib/src/test/java/com/diffplug/spotless/npm/SimpleJsonWriterTest.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.junit.Assert.*;
diff --git a/lib-extra/src/test/java/com/diffplug/spotless/extra/npm/TsFmtFormatterStepTest.java b/testlib/src/test/java/com/diffplug/spotless/npm/TsFmtFormatterStepTest.java
similarity index 98%
rename from lib-extra/src/test/java/com/diffplug/spotless/extra/npm/TsFmtFormatterStepTest.java
rename to testlib/src/test/java/com/diffplug/spotless/npm/TsFmtFormatterStepTest.java
index cbee2df1a4..773f355ecf 100644
--- a/lib-extra/src/test/java/com/diffplug/spotless/extra/npm/TsFmtFormatterStepTest.java
+++ b/testlib/src/test/java/com/diffplug/spotless/npm/TsFmtFormatterStepTest.java
@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.diffplug.spotless.extra.npm;
+package com.diffplug.spotless.npm;
 
 import java.io.File;
 import java.nio.charset.StandardCharsets;