Node.js - How to import dependency modules in public folder under express

Question

Node.js - How to import dependency modules in public folder under express

I created a simple node.js project using the command "express -e sample".

I have my javascript, css files under /public directory and ejs files under views and my server.js is in root directory.

I created a form page and when users submits it, i invoke a function in one of my js files which is under /public/javascripts.

Everything works perfectly. I now want to save the form input to my database(mysql) so i tried to get mysql but it failed. The alert statement said the object is undefined.

var database = require('mysql').Client;

However the same command works fine in server.js. It prints my database properties.

node.js
express

Answer 1

<input type="submit" onclick="processFormData();"/> is the code that invokes processFormData(); function on the client-side (in the browser), once the user clicks the button.

Thus, var database = require('mysql').Client; is also executed on the client.

Obviously, there is no require in the browser; and even if there was require and mysql library in the browser - probably you would still want to make changes in DB from the server, not from the client (not sending to the client your DB credentials).

In order to do that, you should:

Remove the onclick handler and let the user submit the form;
On the server, process the submitted form data and do whatever you want with DB.

Alternatively, if you want to use your current "write once, run anywhere" approach, you may be interested in alternative platforms such as Meteor and OPA language