Node script to search npmjs.com for packages that share one or more given packages as dependencies, i.e. what packages have x, y, and z as dependencies?

dep-check.js

const https = require('https');
const { Transform } = require('stream');

//each package listed as depending on another is in its own <section>
const breakIntoSections = () => new Transform({
  transform(ch, _, cb) {
    const rows = ((this.partialRow || '') + ch.toString()).split(/<\/section>/);
    this.partialRow = rows.pop();
    for (const row of rows) {
      this.push(`${row}\n`);
    }
    cb();
  },
  flush(cb) {
    this.push(this.partialRow || '');
    cb();
  },
});

//each <section> has one <h3> with the package name
const getH3s = () => new Transform({
  transform(ch, _, cb) {
    const str = ch.toString();
    if (/<h3.+h3>/g.test(str)) {
      const newstr = str.match(/<h3.+h3>/g, '');
      this.push(`${newstr}\n`);
    }
    cb();
  },
});

//get package name from <h3>
const getPackageNames = (arr, resolve) => new Transform({
  transform(ch, _, cb) {
    const str = ch.toString();
    const newstr = str.match(/>.+(?=<\/h3)/g, '')[0].slice(1);
    if (!newstr.startsWith('Help')) {
      arr.push(newstr);
    }
    cb();
  },
  flush(cb) {
    resolve(arr);
    cb();
  },
});

//stream web page of packages that depend on the given package
async function getData(offset, arr, pkg) {
  return new Promise((resolve) => {
    setTimeout(() => {
      https.get(`https://www.npmjs.com/browse/depended/${pkg}?offset=${offset}`, (chunks) => chunks
        .pipe(breakIntoSections())
        .pipe(getH3s())
        .pipe(getPackageNames(arr, resolve)));
    }, process.argv.slice(2).length * 1000); //if not slowed the calls are fired off as quickly as possible (about 5/second)
    //which seems to exceed the rate limit and the script exits early, plus regular navigation is curtailed.  1 second/package
    //searched is arbitrary but seems to space requests out enough that the server is not bothered
  });
}

//get array of packages that depend on the given package, i.e. what packages use terser as a regular (not dev) dependency?
async function getDepArray(arr, pkg) {
  return new Promise(async (resolve) => {
    let data;
    let offset = 0;
    do {
      data = await getData(offset, [], pkg);
      arr.push(data);
      offset += 36; //36 packages are listed per page
    } while (data.length > 0);
    resolve(arr);
  });
}

//kick off search in parallel, returns array of array(each package) of array(each page), which will be flattened to array of array
async function main(arr) {
  return Promise.all(arr.map((pkg) => getDepArray([], pkg)));
}

//reduce array of array down to one array of package names that share all the given packages as dependencies
function getSharedDeps(arr) {
  return arr.reduce((acc, cur) => acc.filter((e) => cur.includes(e)));
}

//start
main(process.argv.slice(2)) //call with node dep-check.js package1 package2 package3...
  .then((arr) => arr.map((subArr) => subArr.flat())) //array of array of array -> array of array 
  .then((results) => console.log('results: ', getSharedDeps(results)));

There doesn't seem to be a public API for this data. I tried libraries.io but they include dev dependencies and there didn't seem to be a way to exclude them.