environment decoder

Deno package to decode environment variables.

Based on https://www.npmjs.com/package/environment-decoder.

Usage

Import the decodeEnvironment function and call it with an object that defines which decoder to use for each of your environment variables. For example:

import {
  decodeEnvironment,
  asBoolean,
  asString,
  asNumber,
  asStringUnion,
} from "https://deno.land/x/environment_decoder/mod.ts";

const myEnv = decodeEnvironment({
  BASE_URL: asString, // myEnv.BASE_URL will have type 'string'
  ENVIRONMENT: asStringUnion("dev", "qa", "prod"), // myEnv.ENVIRONMENT will have type '"dev" | "qa" | "prod"'
  PORT: asNumber, // myEnv.PORT will have type 'number'
  FEATURE_FLAG: asBoolean, // myEnv.FEATURE_FLAG will have type 'boolean'
  WITH_DEFAULT: asString.withDefault("defaultOption"), // use `.withDefault()` to set default values for optional environment variables
  OPTIONAL: asString.optional, // use `.optional` or `.withDefault(undefined)` to allow the environment variable to be undefined
});

Notes

environment-decoder will throw an exception when:

environment variables are not set and not using .withDefault() or .optional
environment variables cannot be cast to the requested type (for example, using asNumber on abcde)
using asStringUnion or asNumberUnion and the environment variable is not set to one of the allowed values