events.js:292 错误

小编在使用rollup打包时突然报了下面这个错：

events.js:292
      throw er; // Unhandled 'error' event
      ^

Error: spawn rollup ENOENT
    at Process.ChildProcess._handle.onexit (internal/child_process.js:269:19)
    at onErrorNT (internal/child_process.js:465:16)
    at processTicksAndRejections (internal/process/task_queues.js:80:21)
Emitted 'error' event on ChildProcess instance at:
    at Process.ChildProcess._handle.onexit (internal/child_process.js:275:12)
    at onErrorNT (internal/child_process.js:465:16)
    at processTicksAndRejections (internal/process/task_queues.js:80:21) {
  errno: -2,
  code: 'ENOENT',
  syscall: 'spawn rollup',
  path: 'rollup',
  spawnargs: [ '-c' ]
}

在网上也没找到怎么解决，然后准备看一下rollup的帮助文档，当我运行 rollup --help 时，结果出现：-bash: rollup: command not found ，于是重新安装了一下rollup就解决这个问题了。