fix(15398): skip adding line breaks when replacing JS checks directives (microsoft#38086)

Author: a-tarasyuk

src/services/codefixes/disableJsDiagnostics.ts

@@ -16,14 +16,15 @@ namespace ts.codefix {
                 return undefined;
             }
 
+            const newLineCharacter = sourceFile.checkJsDirective ? "" : getNewLineOrDefaultFromHost(host, formatContext.options);
             const fixes: CodeFixAction[] = [
                 // fixId unnecessary because adding `// @ts-nocheck` even once will ignore every error in the file.
                 createCodeFixActionWithoutFixAll(
                     fixName,
                     [createFileTextChanges(sourceFile.fileName, [
                         createTextChange(sourceFile.checkJsDirective
                             ? createTextSpanFromBounds(sourceFile.checkJsDirective.pos, sourceFile.checkJsDirective.end)
-                            : createTextSpan(0, 0), `// @ts-nocheck${getNewLineOrDefaultFromHost(host, formatContext.options)}`),
+                            : createTextSpan(0, 0), `// @ts-nocheck${newLineCharacter}`),
                     ])],
                     Diagnostics.Disable_checking_for_this_file),
             ];

tests/cases/fourslash/codeFixDisableJsDiagnosticsInFile10.ts

@@ -0,0 +1,23 @@
+/// <reference path='fourslash.ts' />
+
+// @allowjs: true
+// @checkJs: true
+// @noEmit: true
+
+// @filename: a.js
+////let x = "";
+////[|x|] = 1;
+
+// verify.codeFixAvailable([
+//     { description: ts.Diagnostics.Ignore_this_error_message.message },
+//     { description: ts.Diagnostics.Disable_checking_for_this_file.message }
+// ]);
+
+verify.codeFix({
+    description: ts.Diagnostics.Disable_checking_for_this_file.message,
+    index: 1,
+    newFileContent:
+`// @ts-nocheck
+let x = "";
+x = 1;`,
+});

tests/cases/fourslash/codeFixDisableJsDiagnosticsInFile9.ts

@@ -0,0 +1,24 @@
+/// <reference path='fourslash.ts' />
+
+// @allowjs: true
+// @checkJs: true
+// @noEmit: true
+
+// @filename: a.js
+////// @ts-check
+////let x = "";
+////[|x|] = 1;
+
+// verify.codeFixAvailable([
+//     { description: ts.Diagnostics.Ignore_this_error_message.message },
+//     { description: ts.Diagnostics.Disable_checking_for_this_file.message }
+// ]);
+
+verify.codeFix({
+    description: ts.Diagnostics.Disable_checking_for_this_file.message,
+    index: 1,
+    newFileContent:
+`// @ts-nocheck
+let x = "";
+x = 1;`,
+});