sprockets2commonjs.js

// This is an onetime script to convert sprockets to commonjs

// $ npm install glob
// $ npm install babel-cli -g
// # Move to your Rails root.
// $ babel-node sprockets2commonjs.js

let glob = require('glob')
let fs = require('fs')
let path = require('path')

const ROOT = "app/assets/javascripts"
const coffeeExpr = /#= require (.*)/g;
const jsExpr = /\/\/= require (.*)/g;
const whitelist = [];

function convertSprocketPathToCommonjsPath(root, fpath, spath) {
  if (/^\./.test(spath)) {
    return spath;
  }
  let relToRoot = path.relative(fpath, root);
  let rel = path.join(relToRoot, spath).replace(/^(\.\.\/)/, "");
  return rel.indexOf("..") > -1 ? rel : "./" + rel;
}

glob.sync(`${ROOT}/**/*`, {nodir: true}).forEach(f => {
  let c = fs.readFileSync(f).toString();
  const expr = path.extname(f) === ".coffee" ? coffeeExpr : jsExpr;
  let ret = c.replace(expr, (_, p) => {
    if (whitelist.find(w => w === p)) { return c;}
    return `require("${convertSprocketPathToCommonjsPath(ROOT, f, p)}")`
  });
  if (ret != c) {
    fs.writeFileSync(f, ret)
  }
});