节点JS Express包含/导入/导出

Question

Okay, so basically I'm trying to learn and get a hang on the export/import modules in Node. I have created a app.js which contains, everything. To make the app.js file a little cleaner and more readable I'm trying to include a .js file from another folder ( middleware/sass.js) , how would I do that?

My sass.js file looks like this:

let sassMiddleware = require('node-sass-middleware');

app.use(
    sassMiddleware({
        src: path.join(__dirname, 'resources/scss'),
        dest: path.join(__dirname, 'public/css'),
        debug: true,
        indentedSyntax: false,
        outputStyle: 'compressed',
        prefix: '/css'
    })
);

How do I "include" that in app.js without having it all there? I would say I try to do something like the PHP include()

Answer 1

You need to either have application instance in separate module, so it could be imported in multiple places:

index.js

require('./sass');
const app = require('./app');
app.listen(...);

app.js

...
const app = express();
module.exports = app;

sass.js

const app = require('./app');
...
app.use(...);

Or use dependency injection and wrap all parts that depend on application instance with a function:

index.js

const app = require('./app');
require('./sass')(app);
app.listen(...);

sass.js

...
module.exports = app => {
  app.use(...);
};