node-hot

🔥 node-hot

node-hot is a Node.js package that will automatically monitor and hot reload modules (stuff that you require).

Based on this article by Kenneth Chung.

Installation

npm install --save-dev node-hot

Usage

// --- main.js ---

// Will only hot reload after this
require('node-hot')
    // Globally configure node-hot (optional)
    .configure({
        // Disable logging (default: false)
        silent: true,

        // Automatically patch all exported classes (default: false)
        patchExports: true,

        // Exclude patterns (default: node_modules)
        exclude: [
            /[\/\\]node_modules[\/\\]/,
            /[\/\\]bower_components[\/\\]/,
            /[\/\\]jspm_packages[\/\\]/
        ]
    });

// Main/entry module can't be reloaded, hence the extra file
require('./app');

// --- app.js ---

class Foo {}
let foo;

if (module.hot) {
    // Reload this module and its dependencies, when they change (optional)
    module.hot.accept();

    // Gets called before reload (optional)
    module.hot.store(stash => {
        stash.foo = foo;
    });

    // Gets called after reload, if there was a store (optional)
    module.hot.restore(stash => {
        foo = stash.foo;
    });

    // Replaces class methods and accessors (optional)
    module.hot.patch(Foo);
}

if (!foo) {
    foo = new Foo();
}

Once you modify a module on disk, node-hot recursively traverses the dependants of that module, looking for an accepting module. Once it finds that it will re-require that module.

You usually only need accept in one of your first modules to run. However, due to the main/entry module being treated differently from the rest by Node.js, you will not be able to accept from the main/entry module, meaning it can't be reloaded.

You can choose to omit accept entirely, in which case node-hot will automatically accept when it reaches a module with no dependants, which will most likely be the modules require'd by your main module.

License

See LICENSE.