#mitto

mitto is a small library that helps package creators search the file directory of the application consuming their package for its relevant config.

Package creators can even drop a .mitto file into their root folder and specify required and optional parameters with type-checking (including descriptive error messages for package consumers if a required parameter is not present or is of the wrong type).

Reasons to use mitto:

• Quick and painless to start writing your package with a user-provided config in mind
• required or optional parameter enforcement with type-checking for your configs
• Descriptive error messages for the user when something is misconfigured
• .mitto gives your package consumers a common area to see what configurations are available and/or expected

Installation

npm install mitto --save

Usage

Using mitto as a simple file/config finder without a .mitto file

    var mitto = require('mitto');

    var myConfig = mitto.loadConfig('config_i_need.json');

    if (myConfig) {
        //DO STUFF
    } else {
        //YELL AT USER AND CONFIGURE THINGS MYSELF
    }

Using mitto for type-checked configuration expression with a .mitto file

Create a .mitto config file in your root folder:

{
    "name" : "name_of_the_config_file_you_expect_the_user_to_provide.json",
    "required" : {
        "areWeHavingFun" : {
            "type" : "boolean",   //valid types: "undefined", "object", "boolean", "number", "string", "symbol", "function"
            "description" : "boolean that represents if we're having fun" // **Optional**, you don't have to include "description"
        },
        "maximumBeerCount" : {
            "type" : "number"
        } 
    },
    "optional" : {
        "partyResponsibly" : {
            "type" : "boolean",
            "description" : "boolean indicating if we should party responsibly",
            "default" : false // **Optional**, the default value if the user doesn't provide a value or doesn't have a configuration at all
        }
    }
}

The code we write will be exactly the same, except anything we get from the user will be compared with your .mitto and type-checked:

    var mitto = require('mitto');

    var myConfig = mitto.loadConfig('config_i_need.json');

    if (myConfig) {
        //DO STUFF
    } else {
        //CONFIGURE THINGS MYSELF
    }

Error Handling

.mitto has required attributes? | User has a configuration file? | Error handling behavior :---------------------------------: | :----------------------------: | :---------------------- Yes | Yes | Only throws errors if user is missing a required parameter or has a parameter of an invalid type. Yes | No | Throws an error that the configuration is missing. No | Yes | Does not throw errors. loadConfig() will return NULL or an object with defaults. No | No | Does not throw errors. loadConfig() will return NULL or an object with defaults.

Tests

npm test

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code.

Release History

• 0.3.0 Unified API under loadConfig. mitto now "requires" the object for you. .mitto is now more explicit and detailed.
• 0.2.0 Switch from object-templating to .mitto templating, separate opinionated call from non-opiniated.
• 0.1.0 Initial release