neezer / node-cfg Goto Github PK

Also relocate tests closer to implementation

If none provided, default to using

if (errors !== null) {
  errors.forEach(error => {
    process.stderr.write(`config error: ${error}\n`);
    process.exit(1);
  }
}

Try with localhost:2435 instead of http://localhost:2435... might not fail when it should, or at least default to HTTP.

Currently readme is wrong:

- const config = cfg<MyConfig>({ check: assert });
+ const [errors, config] = cfg<MyConfig>({ check: assert });

config.aValue === "whatever";

Currently you have to pass in the type you want to cast configuration as into cfg. I think TS is powerful enough to do this for you. Need to learn a bit more about advanced types first...

That would change invocation to

import { cfg } from "@neezer/cfg";

// handled internally
- interface MyConfig {
-   aValue: string;
- }

- // use a typeguard to definitely type your config
- const guard = (value: any): value is MyConfig => {
-   return !!value && "aValue" in value;
- };

- // create an assertion function using the typeguard
- const assert = (v: any) => {
-   if (guard(v)) {
-     return v;
-   } else {
-     throw new Error("not a valid configuration!");
-   }
- };

// given `process.env.A_VALUE === 'whatever'`

- const config = cfg<MyConfig>({ check: assert });
+ const config = cfg();

config.aValue === "whatever";

Should support configuration by flags.

Currently silenced, possibly expose via log level env?

Sometimes we can't use a connection string as-is because it might contain secrets that are hard to manage in a secure way in operations. Thus, we might have all the parts of a URL spread across multiple environment variables, like so:

In this case, cfg should be smart enough to "bundle up" the various parts and still expose the final value as a URL.

Perhaps the configuration for such a value might look like this?

{
  "url": {
    "desc": "a connection string in parts",
    "env": "DB_URL",
    "format": "url",
    "stitchFromParts": {
      "port": "DB_PORT",
      "host": "DB_HOST",
      "username": "DB_USERNAME",
      "password": "DB_PASSWORD",
      "protocol": "DB_PROTOCOL",
      "query": "DB_OPTIONS"
    }
  }
}

Presently, undefined is falsey, and defaults to "false" value. Instead, throw an error if a bool env is not specified.