port dump-db and other tools to TS

dump-db/inc/extension.ts

@@ -0,0 +1,34 @@
+import path from "path";
+import mimeTypes from "mime-types";
+
+function getFileName(note: any, childTargetPath: string, safeTitle: string) {
+    let existingExtension = path.extname(safeTitle).toLowerCase();
+    let newExtension;
+
+    if (note.type === 'text') {
+        newExtension = 'html';
+    } else if (note.mime === 'application/x-javascript' || note.mime === 'text/javascript') {
+        newExtension = 'js';
+    } else if (existingExtension.length > 0) { // if the page already has an extension, then we'll just keep it
+        newExtension = null;
+    } else {
+        if (note.mime?.toLowerCase()?.trim() === "image/jpg") { // image/jpg is invalid but pretty common
+            newExtension = 'jpg';
+        } else {
+            newExtension = mimeTypes.extension(note.mime) || "dat";
+        }
+    }
+
+    let fileNameWithPath = childTargetPath;
+
+    // if the note is already named with extension (e.g. "jquery"), then it's silly to append exact same extension again
+    if (newExtension && existingExtension !== "." + newExtension.toLowerCase()) {
+        fileNameWithPath += "." + newExtension;
+    }
+
+    return fileNameWithPath;
+}
+
+export default {
+    getFileName
+};