Workaround for Yarn bin links problem

fix-bin-links.js

// this file fixes yarn bugs with linked binaries inside docker mounts
const path = require("path");
const fs = require("fs-extra");
const TreeWalker = require("npm-tree-walker");

const SH_TEMPLATE = binPath =>
`#!/bin/sh
if [ -x "$basedir/node" ]; then
  "$basedir/node"  "${binPath}" "$@"
  ret=$?
else
  node  "${binPath}" "$@"
  ret=$?
fi
exit $ret
`;

const CMD_TEMPLATE = binPath =>
`@IF EXIST "%~dp0\\node.exe" (
  "%~dp0\\node.exe"  "${binPath}" %*
) ELSE (
  @SETLOCAL
  @SET PATHEXT=%PATHEXT:;.JS;=;%
  node  "${binPath}" %*
)
`;

function createLink(linkName, templateFn, binPathRelative) {
  const linkPath = path.resolve(process.cwd(), "node_modules", ".bin", linkName);
  fs.writeFile(linkPath, templateFn(binPathRelative), {
    mode: 755,
  });
}

function createLinks(err) {
  if (err) throw new Error(err);

  const walker = new TreeWalker(process.cwd());
  const binLinks = [];

  walker.on("data", pkg => {
    const pkgPath = path.resolve(process.cwd(), pkg.path);
    const real = require(path.join(pkgPath, "package.json"));

    if(real.bin) {
      if(typeof real.bin === "string") {
        console.log(path.join(pkgPath, real.bin));
        binLinks.push({ name: pkg.name, link: path.join(pkgPath, real.bin) });
      } else if(typeof real.bin === "object") {
        Object.keys(real.bin).forEach(name => {
          console.log(path.join(pkgPath, real.bin[name]));
          binLinks.push({
            name: name,
            link: path.join(pkgPath, real.bin[name])
          })
        });
      }
    }
  });

  walker.on("end", () => {
    binLinks.forEach(binLink => {
      if (fs.existsSync(binLink.link)) {
        // Create link for POSIX
        createLink(binLink.name, SH_TEMPLATE, binLink.link);

        // Create link for Windows
        createLink(`${binLink.name}.cmd`, CMD_TEMPLATE, binLink.link);
      }
    });
    console.log("finished fix-bin-links");
  });

  walker.on("error", err => {
    console.error(err);
  });

  walker.run();
}

const binPath = path.resolve(process.cwd(), "node_modules", ".bin");
fs.mkdirp(binPath, createLinks);