求助mac下怎么安装webpack的，谢谢，以下是我安装报错的

[夜幕下的手指]

MacBook-Pro:~ admin$ node -v
v10.15.3
MacBook-Pro:~ admin$ npm -v
6.4.1
MacBook-Pro:~ admin$ sudo npm install webpack -g
Password:
/usr/local/npm_modules/bin/webpack -> /usr/local/npm_modules/lib/node_modules/webpack/bin/webpack.js

> fsevents@1.2.9 install /usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents
> node install

node-pre-gyp WARN Using needle for node-pre-gyp https download
node-pre-gyp WARN Pre-built binaries not installable for fsevents@1.2.9 and node@10.15.3 (node-v64 ABI, unknown) (falling back to source compile with node-gyp)
node-pre-gyp WARN Hit error EACCES: permission denied, mkdir '/usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents/lib'
gyp WARN EACCES user "root" does not have permission to access the dev dir "/Users/admin/.node-gyp/10.15.3"
gyp WARN EACCES attempting to reinstall using temporary dev dir "/usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents/.node-gyp"
gyp WARN install got an error, rolling back install
gyp WARN install got an error, rolling back install
gyp ERR! configure error
gyp ERR! stack Error: EACCES: permission denied, mkdir '/usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents/.node-gyp'
gyp ERR! System Darwin 18.5.0
gyp ERR! command "/usr/local/bin/node" "/usr/local/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "configure" "--fallback-to-build" "--module=/usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents/lib/binding/Release/node-v64-darwin-x64/fse.node" "--module_name=fse" "--module_path=/usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents/lib/binding/Release/node-v64-darwin-x64" "--napi_version=3" "--node_abi_napi=napi" "--napi_build_version=0" "--node_napi_label=node-v64"
gyp ERR! cwd /usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents
gyp ERR! node -v v10.15.3
gyp ERR! node-gyp -v v3.8.0
gyp ERR! not ok
node-pre-gyp ERR! build error
node-pre-gyp ERR! stack Error: Failed to execute '/usr/local/bin/node /usr/local/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js configure --fallback-to-build --module=/usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents/lib/binding/Release/node-v64-darwin-x64/fse.node --module_name=fse --module_path=/usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents/lib/binding/Release/node-v64-darwin-x64 --napi_version=3 --node_abi_napi=napi --napi_build_version=0 --node_napi_label=node-v64' (1)
node-pre-gyp ERR! stack at ChildProcess.<anonymous> (/usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents/node_modules/node-pre-gyp/lib/util/compile.js:83:29)
node-pre-gyp ERR! stack at ChildProcess.emit (events.js:189:13)
node-pre-gyp ERR! stack at maybeClose (internal/child_process.js:970:16)
node-pre-gyp ERR! stack at Process.ChildProcess._handle.onexit (internal/child_process.js:259:5)
node-pre-gyp ERR! System Darwin 18.5.0
node-pre-gyp ERR! command "/usr/local/bin/node" "/usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents/node_modules/node-pre-gyp/bin/node-pre-gyp" "install" "--fallback-to-build"
node-pre-gyp ERR! cwd /usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents
node-pre-gyp ERR! node -v v10.15.3
node-pre-gyp ERR! node-pre-gyp -v v0.12.0
node-pre-gyp ERR! not ok
Failed to execute '/usr/local/bin/node /usr/local/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js configure --fallback-to-build --module=/usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents/lib/binding/Release/node-v64-darwin-x64/fse.node --module_name=fse --module_path=/usr/local/npm_modules/lib/node_modules/webpack/node_modules/fsevents/lib/binding/Release/node-v64-darwin-x64 --napi_version=3 --node_abi_napi=napi --napi_build_version=0 --node_napi_label=node-v64' (1)
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.9 (node_modules/webpack/node_modules/fsevents):
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.9 install: `node install`
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: Exit status 1

+ webpack@4.31.0
updated 1 package in 8.525s
MacBook-Pro:~ admin$ webpack -v
-bash: webpack: command not found
MacBook-Pro:~ admin$