effect-dotenv

dotenv + dotenv-expand as a ConfigProvider implementation for Effect-TS

Installation

pnpm add effect-dotenv

Usage

Use DotEnv.layer(<filename>) to replace the current ConfigProvider with a .env one.

import { Config, Effect } from "effect";
import { DotEnv } from "effect-dotenv";

import { NodeContext } from "@effect/platform-node";

const program = Effect.gen(function* () {
  const config = yield* Config.all({
    value: Config.string("VALUE"),
  });
  yield* Effect.log(`value = ${config.value}`);
}).pipe(
  Effect.provide(DotEnv.layer(".env")),
  Effect.provide(NodeContext.layer),
);

Effect.runPromise(program);

Alternatively, you can employ the DotEnv.layerAsFallback which sets a ConfigProvider that uses the .env as a fallback. It attemps to resolve the given config from the process.env (assuming the current config provider is the default one) and if not found it tries the .env.

In case you need a more customized setup, use the DotEnv.makeConfigProvider which produces an effect constructing the .env ConfigProvider. You'll probably want to use it along with the Layer.setConfigProvider combinator from effect.