Refactor the tracing namespace organization

Also changes the `tracingEnabled.Mode.*` enum to a string union.

src/compiler/tracing.ts

@@ -5,16 +5,10 @@ namespace ts { // eslint-disable-line one-namespace-per-file
     // should be used as tracing?.___
     export let tracing: typeof tracingEnabled | undefined;
     // enable the above using startTracing()
-}
 
-// `tracingEnabled` should never be used directly, only through the above
-/* @internal */
-namespace ts.tracingEnabled { // eslint-disable-line one-namespace-per-file
-    export const enum Mode {
-        Project,
-        Build,
-        Server,
-    }
+    // `tracingEnabled` should never be used directly, only through the above
+    namespace tracingEnabled { // eslint-disable-line one-namespace-per-file
+        type Mode = "project" | "build" | "server";
 
         let fs: typeof import("fs");
 
@@ -56,8 +50,8 @@ namespace ts.tracingEnabled { // eslint-disable-line one-namespace-per-file
             }
 
             const countPart =
-            mode === Mode.Build ? `.${process.pid}-${++traceCount}`
-            : mode === Mode.Server ? `.${process.pid}`
+                mode === "build" ? `.${process.pid}-${++traceCount}`
+                : mode === "server" ? `.${process.pid}`
                 : ``;
             const tracePath = combinePaths(traceDir, `trace${countPart}.json`);
             const typesPath = combinePaths(traceDir, `types${countPart}.json`);
@@ -84,7 +78,7 @@ namespace ts.tracingEnabled { // eslint-disable-line one-namespace-per-file
         /** Stops tracing for the in-progress project and dumps the type catalog. */
         export function stopTracing(typeCatalog?: readonly Type[]) {
             Debug.assert(tracing, "Tracing is not in progress");
-        Debug.assert(!!typeCatalog === (mode !== Mode.Server)); // Have a type catalog iff not in server mode
+            Debug.assert(!!typeCatalog === (mode !== "server")); // Have a type catalog iff not in server mode
 
             fs.writeSync(traceFd, `\n]\n`);
             fs.closeSync(traceFd);
@@ -157,7 +151,7 @@ namespace ts.tracingEnabled { // eslint-disable-line one-namespace-per-file
                             time: number = 1000 * timestamp()) {
 
             // In server mode, there's no easy way to dump type information, so we drop events that would require it.
-        if (mode === Mode.Server && phase === Phase.CheckTypes) return;
+            if (mode === "server" && phase === Phase.CheckTypes) return;
 
             performance.mark("beginTracing");
             fs.writeSync(traceFd, `,\n{"pid":1,"tid":1,"ph":"${eventType}","cat":"${phase}","ts":${time},"name":"${name}"`);
@@ -294,10 +288,8 @@ namespace ts.tracingEnabled { // eslint-disable-line one-namespace-per-file
             tracePath: string;
             typesPath?: string;
         }
-}
+    }
 
-/*@internal*/
-namespace ts { // eslint-disable-line one-namespace-per-file
     // define after tracingEnabled is initialized
     export const startTracing = tracingEnabled.startTracing;
 }

src/executeCommandLine/executeCommandLine.ts

@@ -666,7 +666,7 @@ namespace ts {
         }
 
         if (canTrace(system, compilerOptions)) {
-            startTracing(isBuildMode ? tracingEnabled.Mode.Build : tracingEnabled.Mode.Project,
+            startTracing(isBuildMode ? "build" : "project",
                          compilerOptions.generateTrace!, compilerOptions.configFilePath);
         }
     }

src/tsserver/nodeServer.ts

@@ -861,7 +861,7 @@ namespace ts.server {
             ? stripQuotes(commandLineTraceDir)
             : process.env.TSS_TRACE;
         if (traceDir) {
-            startTracing(tracingEnabled.Mode.Server, traceDir);
+            startTracing("server", traceDir);
         }
 
         const ioSession = new IOSession();