Configuration files (e.g. `.appnamerc`) may be in either [json](http://json.org/example) or [ini](http://en.wikipedia.org/wiki/INI_file) format. **No** file extension (`.json` or `.ini`) should be used. The example configurations below are equivalent:
To ensure that string representations of booleans and numbers are always converted into their proper types (especially useful if you intend to do strict `===` comparisons), consider using a module such as [parse-strings-in-object](https://github.com/anselanza/parse-strings-in-object) to wrap the config object returned from rc.
## Simple example demonstrating precedence
Assume you have an application like this (notice the hard-coded defaults passed to rc):
```
const conf = require('rc')('myapp', {
port: 12345,
mode: 'test'
});
console.log(JSON.stringify(conf, null, 2));
```
You also have a file `config.json`, with these contents:
```
{
"port": 9000,
"foo": "from config json",
"something": "else"
}
```
And a file `.myapprc` in the same folder, with these contents:
```
{
"port": "3001",
"foo": "bar"
}
```
Here is the expected output from various commands:
*Default `mode` from hard-coded object is retained, but port is overridden by `.myapprc` file (automatically found based on appname match), and `foo` is added.*
*Same result as above but `foo` is overridden because command-line arguments take precedence over `.myapprc` file.*
`node . --foo barbar --config config.json`
```
{
"port": 9000,
"mode": "test",
"foo": "barbar",
"something": "else",
"_": [],
"config": "config.json",
"configs": [
"/Users/stephen/repos/conftest/.myapprc",
"config.json"
]
}
```
*Now the `port` comes from the `config.json` file specified (overriding the value from `.myapprc`), and `foo` value is overriden by command-line despite also being specified in the `config.json` file.*
You may pass in your own `argv` as the third argument to `rc`. This is in case you want to [use your own command-line opts parser](https://github.com/dominictarr/rc/pull/12).
