How to call a function from another class into another function

Question

I am trying to implement i18n module in my application. For this i am making a utility that translates the string. It looks like:

import { I18nService } from "nestjs-i18n";

export class UtilsService {  
    constructor(private readonly i18n: I18nService){}
    translateKey(msgKey){ 
        let message = this.i18n.translate(msgKey, {
            lang: 'en'
        })
        return message
    }
}

But now when am trying to use this function somewhere else i get an error. What am i doing wrong??

I am trying to call it in a ResponseError like this:

export class ResponseError implements ResponseFormatter {
  constructor(infoMessage: string, data?: any, errCode?: number) {
    this.success = false;
    this.message = infoMessage;
    this.data = data;
    this.errCode = errCode;
    console.log(UtilsService.translateKey(infoMessage))
    Logger.warn(
      `${new Date().toString() 
        } - [Response]: ${ 
        infoMessage 
        }${data ? ` - ${  JSON.stringify(data)}` : ''}`,
    );
  }

  message: string;

  data: any[];

  errorMessage: any;

  error: any;

  success: boolean;

  errCode: number;
}

Answer 1

You can create a singleton out of UtilsService and export that object instead:

import { I18nService } from "nestjs-i18n";

class I18NTranslator {
    private i18n!: I18nService;  
    constructor(){
      i18n = new I18nService();
    }
    translateKey(msgKey){ 
        let message = this.i18n.translate(msgKey, {
            lang: 'en'
        })
        return message
    }
}

export const UtilsService = new I18NTranslator();