Add npm-init example

Author: fardjad

examples/npm-init.ts

@@ -0,0 +1,161 @@
+import { InteractiveCommand, InteractiveOption } from "../src/index.ts";
+import * as inquirer from "@inquirer/prompts";
+import fs from "node:fs";
+import path from "node:path";
+
+const program = new InteractiveCommand();
+
+const createPackageJson = <T extends Record<string, unknown>>(record: T): T => {
+  const { test, ...otherProperties } = record;
+
+  return Object.fromEntries(
+    Object.entries({
+      ...otherProperties,
+      ...(test
+        ? {
+            scripts: {
+              test: test ?? 'echo "Error: no test specified" && exit 1',
+            },
+          }
+        : {}),
+    }).filter(([_, value]) => value !== undefined),
+  ) as T;
+};
+
+program
+  .version("1.0.0", "-V, --display-version", "output the version number")
+  .hook("preSubcommand", async (thisCommand, actionCommand) => {
+    if (actionCommand.name() !== "init") {
+      return;
+    }
+
+    // Without package.json, npm init prompts for the following:
+    // - name
+    // - version
+    // - description
+    // - entry point
+    // - test command
+    // - git repository
+    // - keywords
+    // - author
+    // - license
+    // When package.json exists, npm init prompts for the following:
+    // - name
+    // - version
+    // - description
+    // - git repository
+    // - author
+    // - license
+
+    let packageJson: Record<string, unknown> = {};
+
+    try {
+      packageJson = JSON.parse(
+        await fs.promises.readFile("package.json", "utf8"),
+      ) as Record<string, unknown>;
+
+      // Disable some prompts when package.json exists
+      const promptsToDisable = [
+        // Entry point
+        "main",
+        "test",
+        "keywords",
+      ];
+      for (const promptToDisable of promptsToDisable) {
+        (
+          actionCommand.options.find(
+            (option) => option.attributeName() === promptToDisable,
+          ) as InteractiveOption
+        )
+          // eslint-disable-next-line unicorn/no-useless-undefined
+          .prompt(undefined);
+      }
+    } catch {}
+
+    for (const [key, value] of Object.entries(packageJson)) {
+      actionCommand.setOptionValueWithSource(key, value, "config");
+    }
+
+    actionCommand.setOptionValueWithSource(
+      "name",
+      packageJson.name ?? path.basename(process.cwd()),
+      "config",
+    );
+  })
+  .command("init")
+  .requiredOption("-n, --name <name>", "package name")
+  .requiredOption("-v, --version <version>", "version", "1.0.0")
+  .option("-d, --description [description]", "description")
+  .option("-m, --main [entry]", "entry point", "index.js")
+  .option("-t, --test [test]", "test command")
+  .option("-g, --git [git]", "git repository")
+  .addOption(
+    new InteractiveOption("-k, --keywords [keywords...]", "keywords").argParser(
+      (value) => value.split(/[ ,]+/g).filter(Boolean),
+    ),
+  )
+  .option("-a, --author [author]", "author")
+  .option("-l, --license [license]", "license", "ISC")
+  .addOption(
+    // This option is defined here for generating the help message
+    new InteractiveOption("-y, --yes", "confirm the creation of package.json")
+      // eslint-disable-next-line unicorn/no-useless-undefined
+      .prompt(undefined),
+  )
+  .action(
+    async (
+      {
+        confirm,
+        // This option is for the subcommand "init". When positional
+        // options are not enabled, this value is always set to the default
+        // value (true)
+        interactive,
+        ...otherOptions
+      },
+      command: InteractiveCommand,
+    ) => {
+      let newConfirm = confirm === true || confirm === undefined;
+
+      const isInteractive = Boolean(command.optsWithGlobals().interactive);
+      if (isInteractive) {
+        console.log(
+          JSON.stringify(createPackageJson(otherOptions), undefined, 2),
+        );
+
+        newConfirm = await inquirer.confirm({
+          message: "Is this OK?",
+          default: Boolean(newConfirm),
+        });
+      }
+
+      if (!newConfirm) {
+        console.log("Aborted.");
+        return;
+      }
+
+      console.log("TODO: create package.json with the following contents:");
+      console.log(
+        JSON.stringify(createPackageJson(otherOptions), undefined, 2),
+      );
+    },
+  );
+
+await program
+  .interactive("-I, --no-interactive", "disable interactive mode")
+  .parseAsync()
+  .catch((error) => {
+    if (
+      !(
+        error instanceof Error &&
+        error.message.startsWith("User force closed the prompt with")
+      )
+    ) {
+      // eslint-disable-next-line @typescript-eslint/no-throw-literal
+      throw error;
+    }
+  });
+
+// Try the following commands, with and without a package.json in the current working directory:
+// npm-init init
+// npm-init init --name foo
+// npm-init init -I --name foo --version "2.0.0"