fix(node/prettier): dirty hack to allow prettier to find plugins installed with volta

Volta installs all global packages into their own separate sandbox, with
no other packages installed in the same node_modules directory.

This hack abuses the fact that prettier can be configured with a *.js
file, and effectively scans the volta installation directory for
sandboxes for prettier plugins, and sets anything it finds as the
"pluginSearchDirs" list.

install.sh

@@ -28,6 +28,7 @@ SYMLINKS=(
   irbrc
   peco
   powconfig
+  prettierrc.js
   pryrc
   reek.yml
   rspec

prettierrc.js

@@ -0,0 +1,50 @@
+const homedir = require('os').homedir();
+const fs = require("fs");
+
+function voltaPrettierSearchDirs(voltaDir) {
+  const packagesDir = `${voltaDir}/tools/image/packages`;
+
+  let paths = []
+  let parents = [];
+
+  fs.readdirSync(packagesDir).forEach((item) => {
+    if (/^prettier-plugin-[^/]+$/.test(item)) {
+      paths.push(`${packagesDir}/${item}/lib`);
+    }
+
+    if (item == '@prettier') {
+      paths = paths.concat(
+        findDirs(`${packagesDir}/@prettier`, /^plugin-[^/]+$/, "lib")
+      );
+    } else if (/^@[^/]+$/.test(item)) {
+      parents.push(`${packagesDir}/${item}`);
+    }
+
+    return [];
+  })
+
+  parents.forEach((parent) => {
+    paths = paths.concat(findDirs(parent, /^prettier-plugin-[^/]+$/, "lib"));
+  })
+
+  return paths;
+}
+
+function findDirs(parent, pattern, suffix) {
+  return fs.readdirSync(parent).flatMap((item) => {
+    const fp = `${parent}/${item}`;
+    if (pattern.test(item) && fs.statSync(fp).isDirectory()) {
+      if (suffix) {
+        return `${fp}/${suffix}`;
+      }
+      return fp;
+    }
+
+    return [];
+  });
+
+}
+
+module.exports = {
+  pluginSearchDirs: voltaPrettierSearchDirs(`${homedir}/.volta`),
+};