I checked here first before I come here.
My question is a little different than that.
I have following folder structure.
app.js
global.config.js
node-modules
my module
module.config.js
index.js
global.config.js:
var config = {};
config.loggingLevel: "error"; // global setting for all custom modules
module.config.js:
var config = {};
config.loggingLevel: "info"; // ideally should override global setting
index.js
var globalDir = path.dirname(require.main.filename) + "\\global.config.js";
var globalConfig = require(globalDir);
var moduleConfig = require("./module.config.js");
// merge configs here and use only one config object
As seen here, I have a global and module specific config files. I would like to merge them into one config file and use that way.
Is there any way to achieve this easily? (Like a pre-written module) Or should I iterate through each property and override if same key exists?
I wrote a module located under https://github.com/quimsy/espresso which contains a Config Tree Builder. Its (partly) a port of Symfony's Config Component.
You can define a configuration tree:
var TreeBuilder = require("Espresso/Config/Definition/Builder/TreeBuilder");
var builder = new TreeBuilder();
var root = builder.root("connection");
root
.children()
.scalarNode("host").defaultValue("localhost").end()
.end();
And with a Processor You can merge multiple configurations respecting these rules:
var Processor = require("Espresso/Config/Definition/Processor");
var processor = new Processor();
var mergedConfiguration = processor.process( root.getNode(), [ config1, config2 ] );
Regarding the example above, You would do something like:
var builder = new (require("Espresso/Config/Definition/Builder/TreeBuilder")();
var root = builder.root("myConfigRoot");
/* some definitions */
var processor = new (require("Espresso/Config/Definition/Processor"))();
var config = processor.process( root.getNode(), [ globalConfig, moduleConfig ] );
Look at Defining and Processing Configuration Values, since this module is 90% compatible - some different naming conventions and taking respect to Array/Objects (in PHP there is only the Array type).
Related
My log.js,
var data ;
var winston = require('winston');
var config = {'status':1};
module.exports.config = config;
My get.js file(from where i want to modify log.js),
exports.getcategories = function (req, res) {
if(log.status == 1){
var data = 'loaded successfully';
}
};
Here i want to modify my data variable in log.js from my get.js,can anyone please suggest help.
You need to read up on Javascript scopes. In order to access any variable in a file or function from outside it, there are only two ways:
Make the variable global (NOT a good idea).
Create getter/setter functions and export them, thereby exposing it to the outside world
I have seen lots of posts online about how to use a set of variables defined in a file using a require statement.
I want to know how I can use two files.
For example, in pseudo...
gulp --env=prod
if (env):
defaultConfig = require('./config/default.json')
envConfig = require('./config/prod.json')
config = combine(defaultConfig, envConfig)
else:
config = require('./config/default.json')
// Now i can access everything like so...
console.log(config.name)
console.log(config.minify)
This keeps by config DRY and also means I don't have to create a new file for every environment I have.
I'm new to Gulp but i thought this would be a common requirement however, Google hasn't turned up anything for having defaults merged with env specific settings.
Do i need to write a node module?
You can do it with ES6 function Object.assign:
gulp --env=prod
if (env):
defaultConfig = JSON.parse(require('./config/default.json'))
envConfig = JSON.parse(require('./config/prod.json'))
config = Object.assign(defaultConfig, envConfig)
else:
config = JSON.parse(require('./config/default.json'))
// Now i can access everything like so...
console.log(config.name)
console.log(config.minify)
ES6 is supported in Node so you can use it whenever you want.
EDIT: If you have older versions of Node, you can use extend like Sven Schoenung suggest.
Use yargs to parse command line arguments and extend to combine the two config objects:
var gulp = require('gulp');
var argv = require('yargs').argv;
var extend = require('extend');
var config = extend(
require('./config/default.json'),
(argv.env) ? require('./config/' + argv.env + '.json') : {}
);
gulp.task('default', function() {
console.log(config);
});
Running gulp --env=prod will print the combined config, while simply running gulp will print the default config.
Use the following function :
function combine(a,b){
var temp0 = JSON.stringify(a);
var temp1 = temp0.substring(0, temp0.length-1);
var temp2 = (JSON.stringify(b)).substring(1);
var temp3 = temp1 + "," + temp2;
return JSON.parse(temp3);
}
//in app.js
var x = require("x.js");
var instanceX = new x();
require("./Weather")();
//in Weather.js
instanceX.getName();
In this case instanceX wouldn't exist when referenced from Weather.js. How do I make instanceX accessible in Weather.js?
There are a number of different ways to approach this in module design. One simple way is to just pass the variable to the weather.js constructor:
//in app.js
var x = require("x.js");
var instanceX = new x();
require("./Weather")(instanceX);
//in Weather.js
var instanceX;
module.exports = function(ix) {
instanceX = ix;
}
// then elsewhere in the module
instanceX.getName();
I refer to this as the "push" model because you're pushing things to the module that you want to share with it.
I want to somehow create a global singleton module. I'm using it as the context module where I can reference it in any of my modules.
I'll use it to get to my gateway (repository) module for use in other modules like my business object modules etc. So for example let's say I have:
myBusinessModule.js
module.exports = {
find: function(id){
var user = context.userGateway.find(id);
}
};
So I want to be able to use the context singleton to get at other modules in my node app.
Just like the same thing here, this is Java but same concept I want to do something like this in Node.JS: CleanCodeCaseStudy
Based on your comment, to me it looks like you want something like this. Please correct me if i wrongly understood your requirement.
Access with require()
context.js
var context = {};
context.userGateway = require('../path/to/userGateway/module');
module.exports.context = context;
=====================================================================================
//usage in reference file
var context = require('/path/to/context/file');
module.exports = {
find: function(id){
var user = context.userGateway.find(id);
}
};
Access without require()
var context = {};
context.userGateway = require('../path/to/userGateway/module');
GLOBAL.context = context; // makes your context object accessible globally, just like, console, require, module etc.
=====================================================================================
//usage in reference file
module.exports = {
find: function(id){
var user = context.userGateway.find(id);
}
};
I'm really confused about a variable scope issue with a file required via a path in a config file. Why does my Mongoose schema method "see" the required objects when called from within the model file but not when called from my app.js file? I'm convinced that I must be doing something obviously wrong but I can't see it.
The Node project has the following (simplified) structure:
|models
-index.js
-story.js
-post.js
-app.js
-config.js
This is config.js:
config = {};
config.test = 'test';
config.models = __dirname + '/models';
module.exports = config;
This is story.js:
var config = require('../config.js');
var models = require(config.models);
var foo = {};
foo.bar = 'baz';
var storySchema = mongoose.Schema
({
author: {type: mongoose.Schema.Types.ObjectId},
root: {type: mongoose.Schema.Types.ObjectId, default: null}
});
storySchema.methods.test = function()
{
console.log(foo.bar);
console.log(config.test);
console.log(models);
}
var Story = exports.model = mongoose.model('story', storySchema);
When I create a new Story in app.js and call its test() method, I get this output:
baz (so I know it's seeing objects in the same file)
test (so I know it's seeing variables in the config file)
{} (this "should" log my models object but it logs an empty object, why?)
When I create a new Story object within the story.js file, and run it (node ./models.story.js) the values returned are as expected (the models object is logged rather than an empty object).
Update, here are the index.js and app.js files:
index.js:
module.exports = {
post: require('./post'),
story: require('./story')
};
app.js:
var config = require('./config');
var models = require(config.models);
var story = new models.story.model();
story.test();
I believe the issue is that you've created a circular dependency. Story executes require(config.models) which requires Story again inside index.js.
Rather than storing a string and requireing it everywhere, try storing the models directly in config.models:
config.js
module.exports = {
test: 'test',
models: require(__dirname + '/models')
};
In case anyone runs into this same issue, I wanted to point to a couple resources I came across that helped me resolve the issue. As ssafejava pointed out, the problem does have to do with circular dependency (although ssafejava's solution did not entirely resolve the issue) . What worked for me was designing this dependency out of my application but there are other options if doing so is not possible. See the following issues' comments for a better explanation (in particular, see 'isaacs' comments):
https://github.com/joyent/node/issues/1490
https://github.com/joyent/node/issues/1418