Neovim plugin for hot-reload rendering of markdown in the browser.

• CommonMark: uses goldmark, which is CommonMark 0.31.2 compliant.
• Hackable: a tiny codebase makes it easy to modify and extend.
• Images: embed local images with base64 encoding.
• Syntax Highlighting: highlight fenced code blocks.

• Plenary
• Go

Using Lazy.nvim

return {
    "rainstf/mdpreview",
    dependencies = { 'nvim-lua/plenary.nvim' },
    opts = {
        events = {
            reload_on = 'InsertLeave',
            scrolling = false
        }
    },
    keys = {
        { "<leader>ms", "<cmd>MdPreviewStart<cr>" },
        { "<leader>mf", "<cmd>MdPreviewStop<cr>" }
    }
}

You may omit the lazy-loading keys spec and call the user commands directly instead.

This plugin uses a binary executable file to communicate with Neovim and host a web server. It does not come pre-built, so you will need a Go compiler to build it

cd $HOME/.local/share/nvim/lazy/mdpreview && bash ./install.sh

The above shell command automates the build and install process, but performing it manually might be safer.

Alternatively, you could execute the commands:

1. cd $HOME/.local/share/nvim/lazy/mdpreview/binary

Navigate to binary/ in the directory the package manager cloned. For lazy.nvim, cloned plugins are usually found in ~/.local/share/nvim/lazy/

2. go mod tidy && go build .

Ensure all dependencies the binary requires are downloaded. Then build it.

3. sudo cp ./MDPreview /usr/bin

Add it to a directory in PATH. This may require root privileges depending on the location.

If uninstalling, remember to delete the binary executable file.

Configuration is currently limited.

opts = {
    events = {
        reload_on = 'InsertLeave',
        scrolling = false
    }
}

• reload_on: Neovim event used to reload the page. You may specify Neovim events (:h events) for the reload method. For instance, use 'TextChangedI' to update the page content on each keystroke.

• scrolling: Controls automatic page scroll.

The small codebase makes hacking on MDPreview simple and ensures only essential features get implemented. Currently, there's only ~500 LOC and the project will likely never exceed 1k SLOC.

For example,

To change the appearance of the web page, modify the CSS in binary/internal/css.go.

To extend the markdown parser's functionality, view the list of extensions.

MDPreview consists of two components—a Lua script and a Go binary.

Why It Matters: Understanding the plugin-server interaction is crucial if you encounter issues.

Once both components are set up, you can interact with the plugin via its Lua API. The server, a binary executable file, is spawned as a user process and managed by the Lua component. Configuration changes are loaded when the server is spawned. Importantly, these three actions kill the server:

1. Closing the buffer from which it was spawned.
2. Calling the MdPreviewStop command.
3. Closing Neovim.

The buffer's content is sent—on the reload event—to the server over an nvim channel. The server converts the markdown into HTML and sends it to the client (your browser) for rendering using Server Sent Events (SSE).