JS vs JSON for config in Node js [closed]

Question

What should I use for configuration ?

Some module like KrakenJS highly supports configuration through JSON and the blog https://blog.risingstack.com/node-js-best-practices-part-2/ say JS should be preferred over JSON.

Can you tell me how they differ and what's the best way to manage them ?

Answer 1

You should accept both.

JavaScript configuration files have many advantages:

1. programmable of course, which allows for interesting extensions and for generated parts
2. lighter and less awkward to type (less quotes, trailing commas, etc.)
3. lets you have comments (a big limitation of JSON, here's why they're needed)
4. more value types (NaN & infinites, regular expressions for example)

In this case the JS file exports a plain JS object, similar to what you would have had as a result of a parsed JSON file.

JSON is more socially accepted, because JS isn't often thought as a configuration format. Letting people use JSON will prevent a "JS is for logic" sterile debate and there's no problem if people are happy with it.

Accepting both formats:

Here's how reading the JS/JSON configuration can be done:

try {
    config = require('./config.js');
} catch(err) {
    if (err.code==='MODULE_NOT_FOUND') {
        config = require('./config.json');
    } else {
        console.error('config.js loading failed');
        throw err;
    }
}

In any case, the JSON configuration file can be turned to a JS one by just prefixing it with

module.exports =

so nobody's locked in that format.