Function resolve

packages/context/src/resolver.ts:127–164

* Resolve the value or promise for a given injection * @param ctx - Context * @param injection - Descriptor of the injection * @param session - Optional session for binding and dependency resolution

(
  ctx: Context,
  injection: Readonly<Injection>,
  session?: ResolutionSession,
)

 * @param session - Optional session for binding and dependency resolution
 */
function resolve<T>(
  ctx: Context,
  injection: Readonly<Injection>,
  session?: ResolutionSession,
): ValueOrPromise<T> {
  /* istanbul ignore if */
  if (debug.enabled) {
    debug(
      'Resolving an injection:',
      ResolutionSession.describeInjection(injection),
    );
  }

  ctx = resolveContext(ctx, injection, session);
  const resolved = ResolutionSession.runWithInjection(
    s => {
      if (injection.resolve) {
        // A custom resolve function is provided
        return injection.resolve(ctx, injection, s);
      } else {
        // Default to resolve the value from the context by binding key
        assert(
          isBindingAddress(injection.bindingSelector),
          'The binding selector must be an address (string or BindingKey)',
        );
        const key = injection.bindingSelector as BindingAddress;
        const options: ResolutionOptions = {
          session: s,
          ...injection.metadata,
        };
        return ctx.getValueOrPromise(key, options);
      }
    },
    injection,
    session,
  );
  return resolved;
}

/**
 * Given a function with arguments decorated with `@inject`,