Different variable name case convention in one application

Question

This is a really trivial problem. I am just curious on how to deal with this in a "professional" manner.

I am trying to stick to variable naming convention. For NodeJs I am doing camelCasing. For database, I am using PostgreSQL and using underscore_casing.

Now the problem arises when I query data from PostgreSQL. I'll get a user object with following format,

{user_id: 1, account_type : "Admin"}

I can pass this object directly to server side-render and will have to use underscore casing to access account_type. Of course, I can manually create a new user JSON object with property userId and accountType but that is unnecessary work.

Is it possible to follow variable naming convention for both language and avoid having mixed variable names casing in some files? What is a good way to stay organized?

vitaly-t · Accepted Answer · 2022-12-30T01:24:59.487

1

The are two good ways to approach this issue. The simplest one - do no conversion, use the exact database names. And the second one is to camel-case columns automatically.

Either way, you should always follow the underscore notation for all PostgreSQL declarations, as it will give you the option to activate camel-casing in your app at a later time, if it becomes necessary. Never use camel-case inside the database, or you will end up in a lot of pain later.

If you want the best of both worlds, follow the underscore notation for all PostgreSQL declarations, and convert to camel-case as you read data.

Below is an example of how to do it properly with pg-promise, copied from event receive example:

// Example below shows the fastest way to camelize column names:

const options = {
    receive(e) {
        camelizeColumns(e.data);
    }
};

function camelizeColumns(data) {
    const template = data[0];
    for (var prop in template) {
        const camel = pgp.utils.camelize(prop);
        if (!(camel in template)) {
            for (var i = 0; i < data.length; i++) {
                const d = data[i];
                d[camel] = d[prop];
                delete d[prop];
            }
        }
    }
}

Also see the following article: Pg-promise and case sensitivity in column names.

UPDATE

The code above has been updated for use of pg-promise v11 or later.

edited Dec 30 '22 at 01:24

answered Jan 31 '17 at 15:44

vitaly-t

24,279
15
116
138

@Zanko is it interesting enough to accept one of the answers? ;) – vitaly-t Feb 01 '17 at 10:09
I decided to move from node-postgres to pg-promise haha! Do you happen to have any working example on how to establish express-session with pg-promise? – Zanko Feb 01 '17 at 13:47
@Zanko see [simple example](http://mherman.org/blog/2016/03/13/designing-a-restful-api-with-node-and-postgres) and [advanced example](https://github.com/vitaly-t/pg-promise-demo). – vitaly-t Feb 01 '17 at 13:49
yea it doesn't contain how to use it with connect-pg-simple : ( For all I know connect-pg-simple might not even work with pg-promise – Zanko Feb 01 '17 at 13:58
@Zenko, it will work, `pg-promise` exposes `pgp.pg` that can be linked to for your `connect-pg-simple` configuration. – vitaly-t Feb 01 '17 at 15:23

score 0 · Answer 2 · edited May 23 '17 at 12:33

I've struggled with this too, and I've concluded that there's really no way to avoid this kind of ugliness unless you rewrite the objects that come from the database. Fortunately, that's not too difficult in Javascript:

const fromDBtoJS = (obj) => {
    // declare a variable to hold the result
    const result = {};

    // iterate over the keys on the object
    Object.keys(obj).forEach((key) => {
        // adjust the key
        const newKey = key.replace(/_[a-z]/g, (x) => x[1].toUpperCase());

        // add the value from the old object with the new key
        result[newKey] = obj[key];
    });

    // return the result
    return result;
};

Here's a JSFiddle. The "replace" code above was found here

If you wanted to use classes for models in your application, you could incorporate this code into the constructor or database load method so it's all handled more-or-less automatically.

Glad to know I'm not the only one : ) I was worried that my question would be absurd somehow haha. Thanks for you response! — Zanko, Jan 31 '17 at 16:41

Different variable name case convention in one application

2 Answers2