matrix-of-articles-and-authors-from-large-json-dataset.js

const matrix   = {},
      authors  = new Set(),
      articles = data.dataSet.article;

for (let i = 0; i < articles.length; i++) {
  const article = element[i],
        authors = article.authorList;

  for (let j = 0; j < authors.length; j++) {
    const author = fullname(authors[j]);
    authors.add(author);

    for (let k = 0; k < authors.length; k++) {
      const coauthor = fullname(authors[k]);
      matrix[coauthor][author] = (matrix[coauthor][author]++ || 0) + 1;
    }
  }
}