fix[file-header]: fix enforce-trailing-newline option

src/rules/fileHeaderRule.ts

@@ -244,9 +244,7 @@ export class Rule extends Lint.Rules.AbstractRule {
  );
 
  const NEW_LINE_FOLLOWING_HEADER = /^.*((\r)?\n){2,}$/gm;
- return (
- entireComment !== undefined && NEW_LINE_FOLLOWING_HEADER.test(entireComment) !== null
- );
+ return entireComment !== undefined && !NEW_LINE_FOLLOWING_HEADER.test(entireComment);
  }
 
  private getFileHeaderText(

test/rules/file-header/good-newline/test.ts.lint

@@ -0,0 +1,3 @@
+/* Copyright 2019 */
+
+class Foo {}

test/rules/file-header/good-newline/tslint.json

@@ -0,0 +1,10 @@
+{
+ "rules": {
+ "file-header": [
+ true,
+ "Copyright \\d{4}",
+ "Copyright 2019",
+ "enforce-trailing-newline"
+ ]
+ }
+}