在 Nodejs 中同时使用 Currying 和 Module.export

Question

/startup/routes.js

const express = require("express");
const users = require("../routes/users");

module.exports = function(app) {
  app.use(express.json());
  app.use("/api/users", users);
};

index.js

const express = require("express");
const app = express();
require("./startup/routes")(app);

I am confused with the code above, especially the currying in "index.js". Can someone explains me how it works? Generally i am doing the same job as below. What is the difference between them?

index.js

const express = require('express');
const app = express();
app.use(express.json());
app.use('/api/users', require('./routes/api/users'));

Answer 1

routes.js exports a function as its default export. index.js imports and runs the function in one expression:

require("./startup/routes")(app);

That's equivalent to:

const routesFunction = require("./startup/routes");
routesFunction(app);

---

Re your version without a routes.js , it does the same thing the original code does, the only difference is that it's all in one module.