Introduce utils.mjs for misc constants and functions

Move some generic constants and functions, or supporting functions
to a new file.
This makes the main script smaller and makes it more focused on the
core functionality of the module.

scripts/mills_messages.mjs

@@ -1,58 +1,13 @@
-export const module_id = "the-mills-messages";
+import { module_id, history_flag, str_format, create_history_journal } from "./utils.mjs"
-
 import { module_settings, register_settings } from "./settings.mjs";
 import { prepare_send_message_html, validate_form } from "./send_dialog_form.mjs";
 
-// User flag to point to the ID of the journal to store message history to
-const history_flag = "history-journal";
-
 /** @type {SocketlibSocket} */
 let socket;
 const SocketMessages = Object.freeze({
     DisplayMessage: "display-message",
 })
 
-/**
- * This is a copy of Foundry's internal formatting used by
- * localize.format(), so that we can be consistent.
- * @param {String} str The string whose "{named_args}" will be formatted
- * @param {Object} data An object with named_args members, whose data is replaced
- * @returns {String} The formatted string
- */
-function str_format(str, data) {
-    const fmt = /{[^}]+}/g;
-    str = str.replace(fmt, k => {
-        return data[k.slice(1, -1)];
-    });
-    return str;
-}
-
-/**
- * Create the journal entry for the history of the specified user,
- * update the user's history flag and return the entry for further
- * manipulation if needed.
- * @param {User} user The user object that we are creating the history for
- * @return {Promise<JournalEntry>} The JournalEntry that was created.
- */
-async function create_history_journal(user) {
-    // Use the settings' title for the journal, or revert to the default one if it is empty.
-    let format_name = {name: user.character ? user.character.name : user.name};
-    let formated_journal_title = str_format(game.settings.get(module_id, module_settings.HistoryJournalTitle), format_name)
-    let title = formated_journal_title.length > 0 ?
-        formated_journal_title :
-        game.i18n.format("MM.UI.HistoryJournalTitle", format_name)
-
-    return JournalEntry.create({
-        name: title,
-        ownership: {
-            default: CONST.DOCUMENT_OWNERSHIP_LEVELS.NONE,
-            [user.id]: CONST.DOCUMENT_OWNERSHIP_LEVELS.OBSERVER // Make the history private and unmodifiable
-        },
-    }).then(journal => {
-            return user.setFlag(module_id, history_flag, journal.id).then(() => journal);
-        });
-}
-
 /**
  * Handle the dialog to send messages to players from NPCs.
  * The basic dialog is simple : display a few fields selecting which players

scripts/settings.mjs

@@ -1,4 +1,4 @@
-import {module_id} from "./mills_messages.mjs";
+import { module_id } from "./utils.mjs";
 
 export const module_settings = Object.freeze({
     MessageDialogTitle: "messageDialogTitle",

scripts/utils.mjs

@@ -0,0 +1,52 @@
+/*
+ * This file contains some module-wide constants and utility functions
+ * that do not really fit elsewhere.
+ */
+
+import { module_settings } from "./settings.mjs";
+
+export const module_id = "the-mills-messages";
+
+// User flag to point to the ID of the journal to store message history to
+export const history_flag = "history-journal";
+
+/**
+ * This is a copy of Foundry's internal formatting used by
+ * localize.format(), so that we can be consistent.
+ * @param {String} str The string whose "{named_args}" will be formatted
+ * @param {Object} data An object with named_args members, whose data is replaced
+ * @returns {String} The formatted string
+ */
+export function str_format(str, data) {
+    const fmt = /{[^}]+}/g;
+    str = str.replace(fmt, k => {
+        return data[k.slice(1, -1)];
+    });
+    return str;
+}
+
+/**
+ * Create the journal entry for the history of the specified user,
+ * update the user's history flag and return the entry for further
+ * manipulation if needed.
+ * @param {User} user The user object that we are creating the history for
+ * @return {Promise<JournalEntry>} The JournalEntry that was created.
+ */
+export async function create_history_journal(user) {
+    // Use the settings' title for the journal, or revert to the default one if it is empty.
+    let format_name = {name: user.character ? user.character.name : user.name};
+    let formated_journal_title = str_format(game.settings.get(module_id, module_settings.HistoryJournalTitle), format_name)
+    let title = formated_journal_title.length > 0 ?
+        formated_journal_title :
+        game.i18n.format("MM.UI.HistoryJournalTitle", format_name)
+
+    return JournalEntry.create({
+        name: title,
+        ownership: {
+            default: CONST.DOCUMENT_OWNERSHIP_LEVELS.NONE,
+            [user.id]: CONST.DOCUMENT_OWNERSHIP_LEVELS.OBSERVER // Make the history private and unmodifiable
+        },
+    }).then(journal => {
+        return user.setFlag(module_id, history_flag, journal.id).then(() => journal);
+    });
+}