Respect newLine compiler option in language service output (#19279)

Author: weswigham

Diff for: Jakefile.js

@@ -154,6 +154,7 @@ var harnessSources = harnessCoreSources.concat([
     "symbolWalker.ts",
     "languageService.ts",
     "publicApi.ts",
+    "hostNewLineSupport.ts",
 ].map(function (f) {
     return path.join(unittestsDirectory, f);
 })).concat([

Diff for: src/compiler/utilities.ts

@@ -3199,7 +3199,7 @@ namespace ts {
 
     const carriageReturnLineFeed = "\r\n";
     const lineFeed = "\n";
-    export function getNewLineCharacter(options: CompilerOptions | PrinterOptions, system?: System): string {
+    export function getNewLineCharacter(options: CompilerOptions | PrinterOptions, system?: { newLine: string }): string {
         switch (options.newLine) {
             case NewLineKind.CarriageReturnLineFeed:
                 return carriageReturnLineFeed;

Diff for: src/harness/tsconfig.json

@@ -139,6 +139,7 @@
         "./unittests/telemetry.ts",
         "./unittests/languageService.ts",
         "./unittests/programMissingFiles.ts",
-        "./unittests/publicApi.ts"
+        "./unittests/publicApi.ts",
+        "./unittests/hostNewLineSupport.ts"
     ]
 }

Diff for: src/harness/unittests/hostNewLineSupport.ts

@@ -0,0 +1,67 @@
+/// <reference path="..\harness.ts" />
+namespace ts {
+    describe("hostNewLineSupport", () => {
+        function testLSWithFiles(settings: CompilerOptions, files: Harness.Compiler.TestFile[]) {
+            function snapFor(path: string): IScriptSnapshot {
+                if (path === "lib.d.ts") {
+                    return {
+                        dispose() {},
+                        getChangeRange() { return undefined; },
+                        getLength() { return 0; },
+                        getText(_start, _end) {
+                            return "";
+                        }
+                    };
+                }
+                const result = forEach(files, f => f.unitName === path ? f : undefined);
+                if (result) {
+                    return {
+                        dispose() {},
+                        getChangeRange() { return undefined; },
+                        getLength() { return result.content.length; },
+                        getText(start, end) {
+                            return result.content.substring(start, end);
+                        }
+                    };
+                }
+                return undefined;
+            }
+            const lshost: LanguageServiceHost = {
+                getCompilationSettings: () => settings,
+                getScriptFileNames: () => map(files, f => f.unitName),
+                getScriptVersion: () => "1",
+                getScriptSnapshot: name => snapFor(name),
+                getDefaultLibFileName: () => "lib.d.ts",
+                getCurrentDirectory: () => "",
+            };
+            return ts.createLanguageService(lshost);
+        }
+
+        function verifyNewLines(content: string, options: CompilerOptions) {
+            const ls = testLSWithFiles(options, [{
+                content,
+                fileOptions: {},
+                unitName: "input.ts"
+            }]);
+            const result = ls.getEmitOutput("input.ts");
+            assert(!result.emitSkipped, "emit was skipped");
+            assert(result.outputFiles.length === 1, "a number of files other than 1 was output");
+            assert(result.outputFiles[0].name === "input.js", `Expected output file name input.js, but got ${result.outputFiles[0].name}`);
+            assert(result.outputFiles[0].text.match(options.newLine === NewLineKind.CarriageReturnLineFeed ? /\r\n/ : /[^\r]\n/), "expected to find appropriate newlines");
+            assert(!result.outputFiles[0].text.match(options.newLine === NewLineKind.CarriageReturnLineFeed ? /[^\r]\n/ : /\r\n/), "expected not to find inappropriate newlines");
+        }
+
+        function verifyBothNewLines(content: string) {
+            verifyNewLines(content, { newLine: NewLineKind.CarriageReturnLineFeed });
+            verifyNewLines(content, { newLine: NewLineKind.LineFeed });
+        }
+
+        it("should exist and respect provided compiler options", () => {
+            verifyBothNewLines(`
+                function foo() {
+                    return 2 + 2;
+                }
+            `);
+        });
+    });
+}

Diff for: src/services/services.ts

@@ -1146,7 +1146,7 @@ namespace ts {
                 getCancellationToken: () => cancellationToken,
                 getCanonicalFileName,
                 useCaseSensitiveFileNames: () => useCaseSensitivefileNames,
-                getNewLine: () => getNewLineOrDefaultFromHost(host),
+                getNewLine: () => getNewLineCharacter(newSettings, { newLine: getNewLineOrDefaultFromHost(host) }),
                 getDefaultLibFileName: (options) => host.getDefaultLibFileName(options),
                 writeFile: noop,
                 getCurrentDirectory: () => currentDirectory,