prototypeにはえてるプロパティをenumrableなものも取りたいときの方法

gistfile1.js

let fs = require('fs');

function log(targat) {
  const target = targat.prototype;
  const fileName = __dirname + '/dist/' + target.constructor.name + '.txt';

  const props = Object.getOwnPropertyDescriptors(target);
  const str = Object.keys(props).join('\n');
  fs.createWriteStream(fileName).write(str);
}

[Array, RegExp, Object, String, Error, Set, Map, Promise].forEach( target => log(target));

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Enumerability_and_ownership_of_properties

Enumerableをとるか、prototype chainからとるか が一覧になっててわかりやすい