feat: Install less dependencies by default.

glossarify-md now  asks you to (temporarily) install
'inquirer' yourself if it detects the need to upgrade
your glossary configuration. This will save bandwidth
on regular installations and reduce unnecessary
security warnings.

'inquirer' is a library to create interactive
console dialogs. It's used to ask you whether you
want to upgrade and keep a backup of your config.

lib/cli/messages.js

@@ -28,3 +28,17 @@ a different "outDir" or configure "outDirDropOld: false".
 export const OUTDIR_NOT_DELETED =
 `⚠ Could not delete "outDir". Will proceed by copying files...
 `;
+
+export const UPGRADE_REQUIRED =
+`Your configuration needs an upgrade.
+--------------------------------------
+`
+
+export const INQUIRER_REQUIRED =
+`To proceed, please install "inquirer". Then run glossarify-md again.
+
+npm i --no-save inquirer
+
+You will be asked once again before upgrading. In case you do not want
+to upgrade right now, please downgrade glossarify-md to your previous
+version.`

lib/cli/upgrade.js

@@ -1,5 +1,5 @@
 import fs from "fs-extra";
-import inquirer from "inquirer";
+import { INQUIRER_REQUIRED, UPGRADE_REQUIRED } from "./messages.js";
 import { v4To5 } from "./upgrade/v4to5.js";
 import { getFullVersion, getMajorVersion } from "./upgrade/version.js";
 
@@ -47,29 +47,41 @@ function applyUpgrades(userConfData, defaultConfData) {
  * @param {CallableFunction} userConfModifierFn
  */
 function updateConfig(userConfData, userConfFile, defaultConfData, userConfModifierFn) {
-    return inquirer.prompt([{
-        message: "Your configuration needs an upgrade. Keep a copy of the old version?"
-        ,type: "confirm"
-        ,name: "keepBackup"
-        ,required: true
-        ,default: "y"
-    }]).then((answers) => {
-        return new Promise((resolve, reject) => {
-            try {
-                if (answers.keepBackup) {
-                    const backupFile = userConfFile + ".old";
-                    fs.copySync(userConfFile, backupFile);
-                    console.info(`A backup of your previous configuration has been written to '${backupFile}'`);
-                }
-                const newConf = userConfModifierFn.call(undefined, userConfData, defaultConfData);
-                fs.writeFile(userConfFile, JSON.stringify(newConf, null, 2), "utf-8", (err) => {
-                    if (err) { reject(err); }
-                    resolve(newConf);
-                });
-            } catch (error) {
-                reject(error);
-            }
+    console.log(UPGRADE_REQUIRED);
+    return new Promise((resolve, reject) => {
+        const importAsync = import("inquirer");
+        importAsync.catch(err => {
+            console.log(INQUIRER_REQUIRED);
+            reject("");
         });
+        importAsync
+            .then(module => {
+                const inquirer = module.default;
+                return inquirer.prompt([{
+                    message: "Keep a copy of the old version?"
+                    ,type: "confirm"
+                    ,name: "keepBackup"
+                    ,required: true
+                    ,default: "y"
+                }])
+            })
+            .then(answers => {
+                try {
+                    if (answers.keepBackup) {
+                        const backupFile = userConfFile + ".old";
+                        fs.copySync(userConfFile, backupFile);
+                        console.info(`A backup of your previous configuration has been written to '${backupFile}'`);
+                    }
+                    const newConf = userConfModifierFn.call(undefined, userConfData, defaultConfData);
+                    fs.writeFile(userConfFile, JSON.stringify(newConf, null, 2), "utf-8", (err) => {
+                        if (err) { reject(err); }
+                        resolve(newConf);
+                    });
+                } catch (error) {
+                    reject(error);
+                }
+            })
+            .catch(reject);
     });
 }