分配什么 res.json 返回到 Node.js 中的变量

Question

I'm building a social network - and for that I use Node.js. I'm new to the subject, and this's my first post on the subject, I'll be happy if you understand me.

In my social network I want to use an algorithm that has it in the "npm" kmeans algorithm.

I try to keep within a variable what the function returns to me and then continue to do calculations. I think the problem is very minor, but for a few hours I sit on it and can't figure it out.

I'm adding the code of what I've done so far:

//kmeans.js file

const kmeans = require('kmeans-engine');

exports.addUserKmeansMatch = (req, res) => {
  const engineers = [
    // frontend engineers
    { html: 5, angular: 5, react: 3, css: 3 },
    { html: 4, react: 5, css: 4 },
    { html: 4, react: 5, vue: 4, css: 5 },
    { html: 3, angular: 3, react: 4, vue: 2, css: 3 },

    // backend engineers
    { nodejs: 5, python: 3, mongo: 5, mysql: 4, redis: 3 },
    { java: 5, php: 4, ruby: 5, mongo: 3, mysql: 5 },
    { python: 5, php: 4, ruby: 3, mongo: 5, mysql: 4, oracle: 4 },
    { java: 5, csharp: 3, oracle: 5, mysql: 5, mongo: 4 },

    // mobile engineers
    { objc: 3, swift: 5, xcode: 5, crashlytics: 3, firebase: 5, reactnative: 4 },
    { java: 4, swift: 5, androidstudio: 4 },
    { objc: 5, java: 4, swift: 3, androidstudio: 4, xcode: 4, firebase: 4 },
    { objc: 3, java: 5, swift: 3, xcode: 4, apteligent: 4 },

    // devops
    { docker: 5, kubernetes: 4, aws: 4, ansible: 3, linux: 4 },
    { docker: 4, marathon: 4, aws: 4, jenkins: 5 },
    { docker: 3, marathon: 4, heroku: 4, bamboo: 4, jenkins: 4, nagios: 3 },
    { marathon: 4, heroku: 4, bamboo: 4, jenkins: 4, linux: 3, puppet: 4, nagios: 5 }
  ];

  kmeans.clusterize(engineers, { k: 4, maxIterations: 5, debug: true }, (err, result) => {
    res.json(result.clusters)
    .then((data) => {
    let resultCluster = data; //<--- I want to perform a calculation on the object and then return it.
      res.json(resultCluster)
    })
    .catch((err) => {
      console.error(err);
      return res.status(500).json({ error: err.code });
    });
  })
};

//index.js file

const {
  addUserkMeansMatch
} = require('kmeans.js');

app.get('/kmeans', addUserkMeansMatch);
exports.api = functions.region('europe-west1').https.onRequest(app);

The problem is: I want to insert the information that the kmeans.clusterize function returns into the resultCluster object. I can not enter information into the resultCluster.

Then I want to perform calculations with resultCluster and return what I will have in the calculations with resultCluster.

Answer 1

You're calling res.json() twice, and you're using promise syntax on it for no reason. It should be simply

kmeans.clusterize(engineers, { k: 4, maxIterations: 5, debug: true }, (err, result) => {
  if (err) {
    console.error(err);
    res.status(500).json({ error: err.code });
  } else {
    const data = result.clusters; 
    … // perform a calculation on the object
    res.json(data);
  }
})