Convert to it!

Truly universal online file converter.

Many online file conversion tools are boring and insecure. They only allow conversion between two formats in the same medium (images to images, videos to videos, etc.), and they require that you upload your files to some server.

This is not just terrible for privacy, it's also incredibly lame. What if you really need to convert an AVI video to a PDF document? Try to find an online tool for that, I dare you.

Convert.to.it aims to be a tool that "just works". You're almost guaranteed to get an output - perhaps not always the one you expected, but it'll try its best to not leave you hanging.

For a semi-technical overview of this tool, check out the video: https://youtu.be/btUbcsTbVA8

Usage

1. Go to convert.to.it
2. Click the big blue box to add your file (or just drag it on to the window).
3. An input format should have been automatically selected. If it wasn't, yikes! Try searching for it, or open an issue if it's really not there.
4. Select an output format from the second list. If you're on desktop, that's the one on the right side. If you're on mobile, it'll be somewhere lower down.
5. Click Convert!
6. Hopefully, after a bit (or a lot) of thinking, the program will spit out the file you wanted. If not, open an issue or cope and seethe.

Deployment

Here's how to deploy this project locally:

1. Clone this repository.
2. Install Bun.
3. Run bun install to install dependencies.
4. Run bunx vite to start the development server.

The following steps are optional, but recommended for performance:

When you first open the page, it'll take a while to generate the list of supported formats for each tool. If you open the console, you'll see it complaining a bunch about missing caches.

After this is done (indicated by a Built initial format list message in the console), use printSupportedFormatCache() to get a JSON string with the cache data. You can then save this string to cache.json to skip that loading screen on startup.

Contributing

The best way to contribute is by adding support for new file formats (duh). Here's how that works:

Creating a handler

Each "tool" used for conversion has to be normalized to a standard form - effectively a "wrapper" that abstracts away the internal processes. These wrappers are available in src/handlers.

Below is a super barebones handler that does absolutely nothing. You can use this as a starting point for adding a new format:

// file: dummy.ts

import type { FileData, FileFormat, FormatHandler } from "../FormatHandler.ts";

class dummyHandler implements FormatHandler {

  public name: string = "dummy";
  public supportedFormats?: FileFormat[];
  public ready: boolean = false;

  async init () {
    this.supportedFormats = [
      {
        name: "Portable Network Graphics",
        format: "png",
        extension: "png",
        mime: "image/png",
        from: false,
        to: false,
        internal: "png"
      },
    ];
    this.ready = true;
  }

  async doConvert (
    inputFiles: FileData[],
    inputFormat: FileFormat,
    outputFormat: FileFormat
  ): Promise<FileData[]> {
    const outputFiles: FileData[] = [];
    return outputFiles;
  }

}

export default dummyHandler;

For more details on how all of these components work, refer to the doc comments in src/FormatHandler.ts. You can also take a look at existing handlers to get a more practical example.

There are a few additional things that I want to point out in particular:

• Pay attention to the naming system. If your tool is called dummy, then the class should be called dummyHandler, and the file should be called dummy.ts.
• The handler is responsible for setting the output file's name. This is done to allow for flexibility in rare cases where the full file name matters. Of course, in most cases, you'll only have to swap the file extension.
• The handler is also responsible for ensuring that any byte buffers that enter or exit the handler do not get mutated. If necessary, clone the buffer by wrapping it in new Uint8Array().
• When handling MIME types, run them through normalizeMimeType first. One file can have multiple valid MIME types, which isn't great when you're trying to match them algorithmically.

Adding dependencies

If your tool requires an external dependency (which it likely does), there are currently two well-established ways of going about this:

• If it's an npm package, just install it to the project like you normally would.
• If it's a Git repository, add it as a submodule to src/handlers.

Please try to avoid CDNs (Content Delivery Networks). They're really cool on paper, but they don't work well with TypeScript, and each one introduces a tiny bit of instability. For a project that leans heavily on external dependencies, those bits of instability can add up fast.

• If you need to load a WebAssembly binary (or similar), add its path to vite.config.js and target it under /convert/wasm/. Do not link to node_modules.