Feature/put serve behind feature flag (#455)

* Add build-time feature flag capabilities

* Toggle `bw serve` command with `serve` flag

* Run linter and prettier

src/flags.ts

@@ -0,0 +1,5 @@
+export type Flags = {
+  serve?: boolean;
+};
+
+export type FlagName = keyof Flags;

src/program.ts

@@ -468,22 +468,24 @@ export class Program extends BaseProgram {
         this.processResponse(response);
       });
 
-    program
-      .command("serve")
-      .description("Start a RESTful API webserver.")
-      .option("--port <port>", "The port to run your API webserver on. Default port is 8087.")
-      .on("--help", () => {
-        writeLn("\n  Examples:");
-        writeLn("");
-        writeLn("    bw serve");
-        writeLn("    bw serve --port 8080");
-        writeLn("", true);
-      })
-      .action(async (cmd) => {
-        await this.exitIfNotAuthed();
-        const command = new ServeCommand(this.main);
-        await command.run(cmd);
-      });
+    if (CliUtils.flagEnabled("serve")) {
+      program
+        .command("serve")
+        .description("Start a RESTful API webserver.")
+        .option("--port <port>", "The port to run your API webserver on. Default port is 8087.")
+        .on("--help", () => {
+          writeLn("\n  Examples:");
+          writeLn("");
+          writeLn("    bw serve");
+          writeLn("    bw serve --port 8080");
+          writeLn("", true);
+        })
+        .action(async (cmd) => {
+          await this.exitIfNotAuthed();
+          const command = new ServeCommand(this.main);
+          await command.run(cmd);
+        });
+    }
   }
 
   protected processResponse(response: Response, exitImmediately = false) {

src/utils.ts

@@ -9,6 +9,7 @@ import { CollectionView } from "jslib-common/models/view/collectionView";
 import { FolderView } from "jslib-common/models/view/folderView";
 
 import { NodeUtils } from "jslib-common/misc/nodeUtils";
+import { FlagName, Flags } from "./flags";
 
 export class CliUtils {
   static writeLn(s: string, finalLine: boolean = false, error: boolean = false) {
@@ -174,4 +175,18 @@ export class CliUtils {
   static convertBooleanOption(optionValue: any) {
     return optionValue || optionValue === "" ? true : false;
   }
+
+  static flagEnabled(flag: FlagName) {
+    return this.flags[flag] == null || this.flags[flag];
+  }
+
+  private static get flags(): Flags {
+    const envFlags = process.env.FLAGS;
+
+    if (typeof envFlags === "string") {
+      return JSON.parse(envFlags) as Flags;
+    } else {
+      return envFlags as Flags;
+    }
+  }
 }