node_modules/npm/lib/cache/cached-package-root.js

var assert = require("assert")
var resolve = require("path").resolve

var npm = require("../npm.js")

module.exports = getCacheRoot

function getCacheRoot (data) {
  assert(data, "must pass package metadata")
  assert(data.name, "package metadata must include name")
  assert(data.version, "package metadata must include version")

  return resolve(npm.cache, data.name, data.version)
}