Summarizes repo language stats for top 100 (by star count) user owned repos to get a "feel" for user language preference/experience. Replace GITHUB_USERNAME with a user you want to summarize and YOUR_GITHUB_API_TOKEN with the access token (https://help.github.com/articles/creating-a-personal-access-token-for-the-command-line/)

summarize_github_stats.js

"use strict";

const https = require("https");
const API_TOKEN = "YOUR_GITHUB_API_TOKEN";
const GITHUB_USER = "GITHUB_USERNAME";

const request = (options, postBody) => {
  return new Promise((resolve, reject) => {
    const req = https.request(options, res => {
      let body = "";
      res.setEncoding("utf8");
      res.on("data", data => (body += data));
      res.on("end", () => resolve(JSON.parse(body)));
    });

    req.on("error", reject);
    req.write(JSON.stringify(postBody));
    req.end();
  });
};

const getQuery = (user, limit = 100) => ({
  query: `query ($limit: Int!, $user: String!) {
        user(login: $user) {
          contributedRepositories(first: $limit, orderBy: {field: STARGAZERS, direction: DESC}) {
            edges {
              node {
              name
              owner {
                login
              }
              languages(first: $limit) {
                totalSize
                totalCount
                edges {
                  size
                  node {
                    name
                  }
                }
              }
            }
          }
        }
      }
    }`,
  variables: `{
      "limit": ${limit},
      "user": "${user}"
    }`
});

const getUserPublicProjectStats = async user => {
  const {
    data: { user: { contributedRepositories: { edges: repos } } }
  } = await request(
    {
      hostname: "api.github.com",
      port: 443,
      protocol: "https:",
      path: "/graphql",
      method: "POST",
      headers: {
        Authorization: `bearer ${API_TOKEN}`,
        "User-Agent": "github_api v0.1",
        "Content-Type": "application/json",
        "Content-Length": Buffer.byteLength(JSON.stringify(getQuery(user))),
        "Cache-Control": "no-cache"
      }
    },
    getQuery(user)
  );

  let totalLanguageLines = {};
  const stats = repos
    .filter(r => r.node.owner.login === user)
    .map(({ node: { name, languages, languages: { edges } } }) => ({
      name,
      languages: edges.reduce(
        (mapped, { node: { name }, size }) =>
          Object.assign(mapped, {
            [name]: {
              size,
              percent: `${Math.round(size / languages.totalSize * 10000) /
                100}%`
            }
          }),
        {}
      )
    }));

  stats.forEach(({ languages }) => {
    Object.keys(languages).forEach(name => {
      totalLanguageLines[name] = totalLanguageLines[name] || 0;
      totalLanguageLines[name] += languages[name].size;
    });
  });

  let totalLanguageLinesSum = Object.keys(totalLanguageLines).reduce(
    (total, lang) => totalLanguageLines[lang] + total,
    0
  );

  let totals = Object.keys(totalLanguageLines)
    .sort((a, b) => totalLanguageLines[b] - totalLanguageLines[a])
    .map(
      lang =>
        `${lang}: ${Math.round(
          totalLanguageLines[lang] / totalLanguageLinesSum * 10000
        ) / 100}%`
    )
    .join("\n");

  return {
    stats,
    totals
  };
};

getUserPublicProjectStats(GITHUB_USER).then(({ stats, totals }) => {
  console.log("Repo stats:\n");
  console.log(JSON.stringify(stats, null, 2));
  console.log("\n\nTotals:\n");
  console.log(totals);
});