[SOLVED] Function in module.exports "is not a function"? – nodejs

Issue

I’m trying to use badPort function inside another function (getPort) in module.exports like so:

DEFAULT_PORT = 80;

module.exports = {
        badPort:
                (c_port, min=80, max=90) => {
                        return isNaN(c_port) || !between(c_port, min, max);
                },
        getPort:
                (c_port, min=80, max=90) => {
                        console.log(this.badPort(c_port));
                        return this.badPort(c_port) ? 80 : c_port;
                },
};     

However, when I use this.badPort(c_port) it throws an exception:

TypeError: this.badPort is not a function

But it’s clearly a function as initialised right above it.

If however I take out the (), this.badPort always returns undefined.

Why is this happening and how would I be able to correctly use the function inside module.exports? Is it possible to also declare the "Global variable" DEFAULT_PORT in module.exports this way?

Solution

You can do it, by changing this to module.exports:

DEFAULT_PORT = 80;

module.exports = {
        badPort:
                (c_port, min=80, max=90) => {
                        return isNaN(c_port) || !between(c_port, min, max);
                },
        getPort:
                (c_port, min=80, max=90) => {
                        console.log(module.exports.badPort(c_port));
                        return module.exports.badPort(c_port) ? 80 : c_port;
                },
};

And about second question… you would have to redefine your module, to use that variable externally, like this:

module.exports.DEFAULT_PORT = 80;

Then you will have access to it:

var mod = require('mymodule');
console.log(mod.DEFAULT_PORT);

I am not aware of any other way.

Answered By – Flash Thunder

Answer Checked By – David Goodson (BugsFixing Volunteer)