Type-safe, Easy To Use, Deno Configuration

Getting Started

Getting started with coffee is as easy as writing two lines of code …

// coffee.ts
import coffee from "https://deno.land/x/coffee/mod.ts";
const dbName: string = coffee.get("database.name").string();

- coffee.ts
- config
  - default.json

// default.json
{
  "database": {
    "name": "my-db-name",
  }
}

and run

deno run --allow-read --allow-env coffee.ts

Type Safety

coffee’s goal is to have the most safe types, so you can get the configurations in the desired types.

const name: string = coffee.get("person.name").string();
const age: number = coffee.get("person.age").number();
const passed: boolean = coffee.get("person.test.passed").boolean();

NOTE

coffee saves raw, unkwnown type values in value property of result of get method.

const magical: unknown = coffee.get("person.superpower").value;

Has & Set

check configuration is available on config files with has method and set new configuration during runtume with set.

coffee.has("requests.limit"); // false
coffee.set("requests.limit" , 100);
coffee.has("requests.limit"); // true

Custom Environment Variables

If you want to use environment variables, just create a file called custom-environment-variable and give it values that you want to read from environment variables.

ENV_NAME=coffee

- coffee.ts
- config
  - custom-environment-variables.json

  // custom-environment-variables.json 
  {
   "name" : "ENV_NAME"
  }

// coffee.ts
import coffee from "https://deno.land/x/coffee/mod.ts";
const name: string = coffee.get("database.name").string(); // coffee, reads from ENV_NAME environment variable

Related Environment Variables

coffee can read related environment variables from desired environment specified in DENO_ENV env.

DENO_ENV=production

- coffee.ts
- config
  - production.json

  // production.json
  {
   "something" : "amazing"
  }

// coffee.ts
import coffee from "https://deno.land/x/coffee/mod.ts";
const name: string = coffee.get("something").string();

Customize Coffee Load

coffee can read the configurations from the desired directory.

- coffee.ts
- custom
  - default.json
  - cev.json
  - production.json

// coffee.ts
import coffee from "https://deno.land/x/coffee/mod.ts";
coffee.load({ 
   configDir: "./custom", // specify the custom config directory
   customEnvVarFileName: "cev", // specify the desired custom environment variable config file name
   env: "production" // force relative environment variables to loads from this env
},);
const dbName: string = coffee.get("database.name").string();

Error Handling

coffee tries to make a specific Error for each situation.

import coffee, { errors } from "../mod.ts";

try {
  coffee.load({ configDir: "./bad-config-dir" });
} catch (e) {
  if (e instanceof errors.NoConfigDir) {
    // now IDE knows about "e" and can provide hints.
    e.message; // "./bad-config-dir" directory is not exists.
  }
}

there are 4 kinds of Error Classes that exported from coffee module:

NoConfigDir : throwed when no config dir available.

NoConfigFile : throwed when there is no valid config file in config directory.

BadConfigPath : throwed when tries to get an undefined path from configs.

BadConfigType : throwed when tries to get an config with wrong type.

Supported Formats

We currently support these formats :

json

{
  "database":{
    "name" : "my-db-name"
  }
}

yml

database:
  name: my-db-name

Examples

A number of examples are included in examples folder.

Contributing

We are very pleased with your cooperation, so feel free to open issues and pull requests.