我也遇到了这个问题，这让我发疯。

I had this problem as well, and it was driving me crazy.

最终解决的问题是运行 npm init 。这给我的package.json添加了很多东西，但是随后-save-dev 可以正常工作。即使我删除了 npm init 添加的所有新内容之后，-save-dev 仍然有效。

What finally fixed it was running npm init. This added a bunch of stuff to my package.json, but afterwards --save-dev worked as expected. Even after I removed all the new stuff added by npm init, --save-dev still worked.