trilium/dump-db/inc/extension.ts

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
};