jp-neighboring-pref - 隣接都道府県の一覧をCSVで取り出す（MITライセンス） https://qiita.com/kawanet/items/f753df6249c14ef67a04

jp-neighboring-pref.csv

jp-neighboring-pref.js

#!/usr/bin/env node

const {City} = require("jp-city-lookup");
const {Pref} = require("jp-pref-lookup");

for (let pref = 1; pref <= 47; pref++) {
  const prefName = Pref.name(pref);
  const prefCode = Pref.code(prefName);
  const cities = City.lookup({pref});
  const neMap = {};

  for (const city of cities) {
    const neighboring = City.lookup({neighboring: city});
    for (const neCity of neighboring) {
      const nePref = neCity.substring(0, 2);
      if (+pref !== +nePref) neMap[nePref] = 1;
    }
  }

  const neList = Object.keys(neMap).sort();
  neList.unshift("");
  neList.push("");
  const nePref = neList.join("/");
  const neName = neList.map(p => Pref.name(p)).join("/");
  console.log([prefCode, prefName, nePref, neName].join(","));
}