需要再

cnpm install npm

一下

代码参考 http://npm.taobao.org/package/npm

var npm = require("npm")
npm.load(myConfigObject, function (er) {
  if (er) return handlError(er)
  npm.commands.install(["some", "args"], function (er, data) {
    if (er) return commandFailed(er)
    // command succeeded, and data might have some info
  })
  npm.on("log", function (message) { .... })
})