I'm currently working on a small console project that depends a lot on the arguments that are passed initially and I'm looking for a good way to handle a configuration object in nodejs.

I have the project currently fully working with the following example but I think I'm relaying on the caching of modules when using 'require'.

lets assume a module options.js

'use strict';

var options = {
    configName: '.jstail',
    colorActive: (process.platform === 'win32') ? false : true, // deactivate color by default on windows platform
    quiet: false,
    debug: false,
    config: null,
    logFile: null,
    setting: null
};

module.exports = options;

And my initial module init.js

#!/usr/bin/env node
'use strict';

var options = require('options'); // require above options module

// modify the options object based on args

I then have a logger that depends on this options

For example if quiet is set to true no logging should happen

logger.js

'use strict';

var options = require('options');

/**
 * prints to console if not explicitly suppresed
 * @param {String} text
 */
function log(text) {
   if (!options.quiet) {
       console.log('[LOG]: ' + text);
   }
}

My big problem is (I think) that I'm relaying on the caching of nodejs modules when I require the options module in the logger

So my two questions are:

Am I right that this only works because of the caching of the modules that nodejs does for me? Is there any better way to handle a dynamic global configuration?

I know there are several questions and tutorials around with a config file but thats not what I'm looking for.

I'm currently working on a small console project that depends a lot on the arguments that are passed initially and I'm looking for a good way to handle a configuration object in nodejs.

I have the project currently fully working with the following example but I think I'm relaying on the caching of modules when using 'require'.

lets assume a module options.js

'use strict';

var options = {
    configName: '.jstail',
    colorActive: (process.platform === 'win32') ? false : true, // deactivate color by default on windows platform
    quiet: false,
    debug: false,
    config: null,
    logFile: null,
    setting: null
};

module.exports = options;

And my initial module init.js

#!/usr/bin/env node
'use strict';

var options = require('options'); // require above options module

// modify the options object based on args

I then have a logger that depends on this options

For example if quiet is set to true no logging should happen

logger.js

'use strict';

var options = require('options');

/**
 * prints to console if not explicitly suppresed
 * @param {String} text
 */
function log(text) {
   if (!options.quiet) {
       console.log('[LOG]: ' + text);
   }
}

My big problem is (I think) that I'm relaying on the caching of nodejs modules when I require the options module in the logger

So my two questions are:

Am I right that this only works because of the caching of the modules that nodejs does for me? Is there any better way to handle a dynamic global configuration?

I know there are several questions and tutorials around with a config file but thats not what I'm looking for.

• javascript
• node.js

1 Answer 1

Yes, this only works because of caching, though I wouldn't call it caching (but node.js docs do) rather than lazy initialization. It's ok to rely on that, a lot of modules do some initialization of first require, using it for configuration is also typical. Generally speaking, require is a node.js way of accessing global singleton objects.

The other way to do it is to load configuration from a single file, modify it and then pass it to other modules who need it, like this:

//index.js
var config = require('./config')

config.flag = false

var module1 = require('./module1')(config)

//module1.js
module.exports = function (config) {
// do stuff
}

It makes code more decoupled and testable but adds plexity. Difference between these two approaches is basically the same as using globals vs dependency injection. Use whatever you like.