@norviah/config

Simplifies working with JSON files in tandem with TypeScript. config is a package that allows you to import JSON files against a TypeScript interface, validating the structure of the JSON file.

Installation

npm install @norviah/config

Usage

To use config, you must first create an inteface that defines the desired structure for the JSON file, if desired, this interface can be infinitely deep. From this interface, you must then define a Structure instance for the interface. Structure defines an interaface that is essentially a mapping of each key within the desired interface, each key must be set to an object that defines important properties for that key.

config exports the Config class, which contains various useful methods for parsing JSON files. Importis the main entry point for the package, this is the method that you will use to import JSON files:

Config.Import<T>(structure: Structure<T>, options: Options): T;

Defining the Structure for the interface is the essential part of the package, here is where you can map a JSON value into any desired type you wish. As previously said, Structure represents important information about each key, as each key will represent a KeyOptions instance. The most important property is type, which defines the type of the key, which takes one of the following values:

• a string, or
• a function

If a function is specified, the function will act as the constructor for the key, the return value of the function will be treated as the final value for the key. If the provided value is invalid, the function should return null to indicate this.

If you specify functions, it can be tedious to provide a function for various primitive types, therefore, you can provide a string instead. If the desired type of the key is a primitive type, config will parse and validate the value accordingly, and return the value as the final value for the key. The following are the supported primitive types:

• string
• number
• boolean
• null

Example

As an example, let's say we want to load a JSON file for our Discord bot. The config file will hold two values: token and prefix, both of which are strings.

config.json

{
  "token": "[token]",
  "prefix": "!"
}

main.ts

import { load } from '@norviah/config';

interface Config {
  token: string;
  prefix: string;
}

// Note that you can provide the `type` property as the direct value for the 
// key, as a shortcut for `{ type: "string" }`.
const config: Config = load<Config>(
  {
    token: "string", 
    prefix: "string"
  },
  { path: "[path]" },
);

// Once imported, you can use the config as you would any other object.
console.log(config.token);

Of course, this is a rather simple example, but it demonstrates the basic usage of config. For more examples and information, please refer to the documentation here.