diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index c56debdf251c5..2e4492efa7b14 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1383,7 +1383,7 @@ namespace ts {
                 getSourceFile: program.getSourceFile,
                 getSourceFileByPath: program.getSourceFileByPath,
                 getSourceFiles: program.getSourceFiles,
-                isSourceFileFromNodeModules: (file: SourceFile) => !!lookUp(sourceFilesFoundSearchingNodeModules, file.path),
+                isSourceFileFromExternalLibrary: (file: SourceFile) => !!lookUp(sourceFilesFoundSearchingNodeModules, file.path),
                 writeFile: writeFileCallback || (
                     (fileName, data, writeByteOrderMark, onError, sourceFiles) => host.writeFile(fileName, data, writeByteOrderMark, onError, sourceFiles)),
                 isEmitBlocked,
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index e4111e3f92563..7892af6624f3c 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -36,7 +36,7 @@ namespace ts {
         getSourceFiles(): SourceFile[];
 
         /* @internal */
-        isSourceFileFromNodeModules(file: SourceFile): boolean;
+        isSourceFileFromExternalLibrary(file: SourceFile): boolean;
 
         getCommonSourceDirectory(): string;
         getCanonicalFileName(fileName: string): string;
@@ -2279,7 +2279,7 @@ namespace ts {
             const sourceFiles = targetSourceFile === undefined ? host.getSourceFiles() : [targetSourceFile];
             for (const sourceFile of sourceFiles) {
                 // Don't emit if source file is a declaration file, or was located under node_modules
-                if (!isDeclarationFile(sourceFile) && !host.isSourceFileFromNodeModules(sourceFile)) {
+                if (!isDeclarationFile(sourceFile) && !host.isSourceFileFromExternalLibrary(sourceFile)) {
                     onSingleFileEmit(host, sourceFile);
                 }
             }
@@ -2315,7 +2315,7 @@ namespace ts {
             // --module or --target es6 specified. Files included by searching under node_modules are also not emitted.
             const bundledSources = filter(host.getSourceFiles(),
                 sourceFile => !isDeclarationFile(sourceFile) &&
-                              !host.isSourceFileFromNodeModules(sourceFile) &&
+                              !host.isSourceFileFromExternalLibrary(sourceFile) &&
                               (!isExternalModule(sourceFile) ||
                                !!getEmitModuleKind(options)));
             if (bundledSources.length) {