dancecoder/di-service

Really simple dependency injection solution for JavaScript

di-service's Issues

Improve undefined dependency error message

Currently message looks like this

Incorrect service requirements: undefined requirement

Usually undefined in dependencies happens in case some circular imports/require. So need to add information about requiring class and all dependences in list to help debugging.

Implement support for declare requiring class as a dependency

I would like to implement context based logger service, this logger need context name. Logger constructo may take context name from a class which will use this logger. Tipically loggers are initialized in constructor of a class. With DIService it may be initialized before class instance created.

To be implemented

SERVICE_REQUIRING - symbol, should be substituted by the class-object (not an instance) which caused current class initialization by requirement, other words a class-object which declare current class as a dependency by SERVICE_REQUIRE. See also example below.

NOTE: SERVICE_MULTIPLE must be required if SERVICE_REQUIRING appears in dependency list

Examples

Custom service which requiring for the logger service

class CustomService {
   
   static [SERVICE_REQUIRE] = [ServiceLogger];
   static [LOGGER_CONTEXT] = 'CUSTOM';

   #logger;

   constructor(logger) {
       this.#logger = logger;
   }

   action() {
       this.#logger.log('Action performed'); // => 'CUSTOM Action performed' in console
   }
}

Logger service

const LOGGER_CONTEXT = Symbol();

class ServiceLogger {

   static [SERVICE_REQUIRE] = [SERVICE_REQUIRING];
   static [SERVICE_MULTIPLE] = true;

   #contextName;
   constructor(requiringClz) {
      this.#contextName = requiringClz[LOGGER_CONTEXT] ?? requiringClz.name;
      console.log(requiringClz === CustomService)  // => true
   }
   log(message) {
      console.log(this.#contextName, message);
   }
}