CLI extract command

src/cli/commands/extract.ts

@@ -0,0 +1,29 @@
+import { Asar, BaseEntry } from "../..";
+
+import { readFile, writeFile, mkdir } from "fs/promises";
+
+import { join as joinPaths, dirname } from "path";
+
+export default async function extract(...args: string[]) {
+  const [archive, output] = args;
+
+  const asarBytes = await readFile(archive);
+
+  const asar = new Asar(asarBytes);
+
+  for (const [, filePathChunks, fileEntry] of asar.walkFiles(true)) {
+    if (BaseEntry.isDirectory(fileEntry)) {
+      const fileDirPath = joinPaths(output, ...filePathChunks);
+
+      await mkdir(fileDirPath, {
+        recursive: true,
+      });
+    } else {
+      const filePath = joinPaths(output, ...filePathChunks);
+
+      const fileData = asar.readFile(fileEntry);
+
+      await writeFile(filePath, fileData);
+    }
+  }
+}

src/cli/index.ts

@@ -3,16 +3,26 @@
 import { help } from "./help";
 import { colors, error } from "../log";
 
+import extract from "./commands/extract";
+
 const command = process.argv[2];
 
 if (!command) {
   error("No command specified\n");
   help(2);
 }
 
-const commands = ["extract", "pack", "list", "help"];
+const commands = {
+  extract: extract,
+  pack: console.log, // TODO
+  list: console.log, // TODO
+  help: console.log, // TODO
+};
+type Command = keyof typeof commands;
 
-if (!commands.includes(command)) {
+if (!(command in commands)) {
   error(`Unknown command ${colors.bold(`"${command}"`)}\n`);
   help(2);
 }
+
+commands[command as Command](...process.argv.slice(3));