Knfg

Knfg is a configuration loader for typescript projects. It uses class property reflection to dynamically load configuration from into a class from some arbitrary configuration backend at runtime.

Config Backends

• Environment Variables

In the future, knfg is prioritizing support for AWS DynamoDB and S3. These will come eventually.

Usage

import Knfg from "knfg";

const k = new Knfg({ backend: "env " });

class Config {

  @k.Param({ key: "MONGO_URL" })
  public mongoUrl!: string;

  @k.Param({ key: "SECRET_PASSWORD", optional: true })
  public secretPassword?: string;
}

const config = await k.Load(new Config());

Behavior

By default, all keys are "required", which means that knfg will throw an error if a key is specified but is missing in the backend. You can mark a key as optional: true if you'd like it to be optional and not throw an error if its missing; just be sure to reflect that optionality if the type of that field with a ?;

The only types Knfg supports, at this time and the expected future, are strings, booleans, and numbers.

Knfg will attempt to coerce types. That specific behavior is defined on a per-backend basis:

Env

All environment variables are strings, obviously. So:

• string: Its already a string, to no conversion.
• number: Uses parseInt(value, 10) and will throw an error if it fails.
• boolean: Accepts "true" or "false", case insensitive on both.