app.js
const express = require("express");
const app = express();
app.use("/", require("./routers.js")(app));
app.listen(3000);
router.js
module.exports = function (app) {
console.log(app);
app.get("/", (req, res) => {
res.json(5);
});
};
The error given by the Console is: " TypeError: Router.use() requires a middleware function but got an undefined "
I don't understand why I can't pass the express app(app.js) through routers( in this way I don't redeclare the express and app variable in router.js ).
CodePudding user response：
Don't pass app to routes better to create a new router and pass to the app.
router.js
const express = require("express");
const router = express.Router();
router.get("/", (req, res) => {
res.json(5);
});
module.exports = router;
app.js
app.use("/", require("./routers.js"));
CodePudding user response：
The use method of Express needs a callback of three parameters, not the app itself, so you need something like this:
In routes.js
exports.doSomeThing = function(req, res, next){
console.log("Called endpoint");
res.send("Called endpoint");
}
In your index.js
const Express = require("express");
const app = Express();
const routes = require("./routes");
app.use("/", routes.doSomeThing);
app.listen(3030, () => {
console.log("Listening on port 3030");
});
This approach doesn't need to include the express router but this may not be adecuate for big scale projects I recommend you to read express router documentation: