Use private variables in Application. NFC

As far as I recall these were always intended to be private, but I
was not aware of how widespread support for private variables was.
(In any case, this package is intended to always used with a bundler,
so this isn't a breaking change even if the fields were read.)

Author: whitequark

lib/api.js

@@ -47,34 +47,41 @@ function fetchResources({ modules, filesystem }) {
 }
 
 export class Application {
+    #resources;
+    #resourceData;
+    #instantiate;
+    #argv0;
+
     constructor(resources, instantiate, argv0) {
-        this.resources = resources;
-        this.resourceData = null;
-        this.instantiate = instantiate;
-        this.argv0 = argv0;
+        this.#resources = resources;
+        this.#resourceData = null;
+        this.#instantiate = instantiate;
+        this.#argv0 = argv0;
     }
 
     // The `printLine` option is deprecated and not documented but still accepted for compatibility.
     run(args = null, files = {}, options = {}) {
-        if (this.resourceData === null) {
+        if (this.#resourceData === null) {
             if (options.synchronously)
                 throw new Error("Cannot run application synchronously unless resources are " +
                                 "prefetched first; use `await run()` to do so");
 
-            return this.resources().then(fetchResources).then((resourceData) => {
-                this.resourceData = resourceData;
-                return this.run(args, files, options);
-            });
+            return this.#resources()
+                .then((resourceObject) => fetchResources(resourceObject))
+                .then((resourceData) => {
+                    this.#resourceData = resourceData;
+                    return this.run(args, files, options);
+                });
         }
 
         if (args === null)
             return; // prefetch resources, but do not actually run
 
         // meow. :3
         const environment = new Environment();
-        environment.args = [this.argv0].concat(args);
+        environment.args = [this.#argv0].concat(args);
         environment.root = directoryFromTree(files);
-        for (const [dirName, dirContents] of Object.entries(this.resourceData.filesystem))
+        for (const [dirName, dirContents] of Object.entries(this.#resourceData.filesystem))
             environment.root.files[dirName] = directoryFromTree(dirContents);
         const lineBufferedConsole = lineBuffered(options.printLine ?? console.log);
         environment.stdin  = options.stdin  === undefined ? null : options.stdin;
@@ -92,7 +99,7 @@ export class Application {
                     error = e;
             }
 
-            for (const dirName of Object.keys(this.resourceData.filesystem))
+            for (const dirName of Object.keys(this.#resourceData.filesystem))
                 delete environment.root.files[dirName];
             files = directoryIntoTree(environment.root, { decodeASCII: options.decodeASCII ?? true });
             if (error !== null) {
@@ -103,13 +110,13 @@ export class Application {
             }
         };
 
-        const getCoreModule = (filename) => this.resourceData.modules[filename];
+        const getCoreModule = (filename) => this.#resourceData.modules[filename];
         const imports = { runtime: environment.exports };
         if (options.synchronously) {
             const instantiateCore = (module, imports) => new WebAssembly.Instance(module, imports);
-            return runCommand(this.instantiate(getCoreModule, imports, instantiateCore));
+            return runCommand(this.#instantiate(getCoreModule, imports, instantiateCore));
         } else {
-            return this.instantiate(getCoreModule, imports).then(runCommand);
+            return this.#instantiate(getCoreModule, imports).then(runCommand);
         }
     }
 }