module.exports 返回未定义

Question

I`m trying to make a translation function with IBM Watson API in " services/ibmWatson/index.js ". I receive the response correctly, but when I return the response to the " IncidentController.js " it receives as undefined.

const LanguageTranslatorV3 = require('ibm-watson/language-translator/v3');
const { IamAuthenticator } = require('ibm-watson/auth');

module.exports = {
    async translate(phrase, language) {

        const languageTranslator = new LanguageTranslatorV3({
            authenticator: new IamAuthenticator({ apikey: '<my_API_key>' }),
            url: 'https://gateway.watsonplatform.net/language-translator/api/',
            version: '2020-03-28',
        });

        await languageTranslator.translate(
            {
                text: phrase,
                source: 'pt',
                target: language
            })
            .then(response => {
                if(response.status=200){
                    console.log(response.result.translations);
                    return(response.result.translations);
                }
                return (["error"]);
            })
            .catch(err => {
                console.log('error: ', err);
                return (["error"]);
            });
    }
}

In the above code the console.log(response.result.translations) returns correctly:

[ { translation: 'Dog run over.' },
  { translation: 'Castration' },
  { translation: 'Ticks' },
  { translation: 'Tuberculosis' } ]

In the in IncidentController.js:

const Watson = require('../../src/services/ibmWatson');
const db_connection = require('../database/connection');

module.exports = {
        async index(request, response) {
            const incidents = await db_connection('incidents').join('ongs', 'ongs.id', '=', 'incidents.ong_id')
                .select([
                        'incidents.*',
                        'ongs.name',
                            'ongs.uf']
                    );

            const titles = [];
            incidents.forEach((incident) => { titles.push(incident.title) });

            const translated_titles = await Watson.translate(titles, "en");
            console.log(translated_titles);

            return response.json(incidents);
    }
}

In the above code the console.log(response.result.translations) returns undefined .

What is wrong with it?

Answer 1

You are returning response.result.translations to the response callback from then() . Since that callback cannot be accessed by your IncidentController, it returns undefined . This is one way to solve this problem:

// services/ibmWatson/index.js
translate(phrase, language) {
   return new Promise((resolve, reject) => {
      try {
         const response = await languageTranslator.translate({ /* options */ });
         resolve(response); // Return the translations
      } catch(error) {
         reject(error); // If there's an error, return the error
      }
   });
}

// IncidentController.js
async index() {
   // ...
   const translatedTitles = await Watson.translate(titles, "en");
   console.log(translatedTitles); // Should be working now
}

I hope I could help you or at least lead you in the right direction.