npm install/uninstall 時に、Cannot find module 'slash' が発生する

Question

事象

npm install / uninstall 時に以下のエラーが発生します。
解決方法をお教えいただきたいです。

ターミナルログ

npm ERR! code MODULE_NOT_FOUND
npm ERR! Cannot find module 'slash'
npm ERR! Require stack:
npm ERR! - /usr/local/lib/node_modules/npm/node_modules/read-package-json/read-json.js
npm ERR! - /usr/local/lib/node_modules/npm/node_modules/read-package-tree/rpt.js
npm ERR! - /usr/local/lib/node_modules/npm/lib/install.js
npm ERR! - /usr/local/lib/node_modules/npm/lib/npm.js
npm ERR! - /usr/local/lib/node_modules/npm/bin/npm-cli.js

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/my_name/.npm/_logs/2020-03-22T01_48_45_735Z-debug.log

2020-03-22T01_48_45_735Z-debug.log

0 info it worked if it ends with ok
1 verbose cli [
1 verbose cli   '/usr/local/bin/node',
1 verbose cli   '/usr/local/bin/npm',
1 verbose cli   'install',
1 verbose cli   '-g',
1 verbose cli   'expo-cli'
1 verbose cli ]
2 info using npm@6.12.1
3 info using node@v12.13.1
4 verbose stack Error: Cannot find module 'slash'
4 verbose stack Require stack:
4 verbose stack - /usr/local/lib/node_modules/npm/node_modules/read-package-json/read-json.js
4 verbose stack - /usr/local/lib/node_modules/npm/node_modules/read-package-tree/rpt.js
4 verbose stack - /usr/local/lib/node_modules/npm/lib/install.js
4 verbose stack - /usr/local/lib/node_modules/npm/lib/npm.js
4 verbose stack - /usr/local/lib/node_modules/npm/bin/npm-cli.js
4 verbose stack     at Function.Module._resolveFilename (internal/modules/cjs/loader.js:797:15)
4 verbose stack     at Function.Module._load (internal/modules/cjs/loader.js:690:27)
4 verbose stack     at Module.require (internal/modules/cjs/loader.js:852:19)
4 verbose stack     at require (internal/modules/cjs/helpers.js:74:18)
4 verbose stack     at Object.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/read-package-json/read-json.js:14:13)
4 verbose stack     at Module._compile (internal/modules/cjs/loader.js:959:30)
4 verbose stack     at Object.Module._extensions..js (internal/modules/cjs/loader.js:995:10)
4 verbose stack     at Module.load (internal/modules/cjs/loader.js:815:32)
4 verbose stack     at Function.Module._load (internal/modules/cjs/loader.js:727:14)
4 verbose stack     at Module.require (internal/modules/cjs/loader.js:852:19)
5 verbose cwd /Users/my_name/myActivity/study/react-native/expo/ISBN978
6 verbose Darwin 19.3.0
7 verbose argv "/usr/local/bin/node" "/usr/local/bin/npm" "install" "-g" "expo-cli"
8 verbose node v12.13.1
9 verbose npm  v6.12.1
10 error code MODULE_NOT_FOUND
11 error Cannot find module 'slash'
11 error Require stack:
11 error - /usr/local/lib/node_modules/npm/node_modules/read-package-json/read-json.js
11 error - /usr/local/lib/node_modules/npm/node_modules/read-package-tree/rpt.js
11 error - /usr/local/lib/node_modules/npm/lib/install.js
11 error - /usr/local/lib/node_modules/npm/lib/npm.js
11 error - /usr/local/lib/node_modules/npm/bin/npm-cli.js
12 verbose exit [ 1, true ]

直前に実施したこと

npm install -g expo

ためしたこと

npm uninstall -g expo => 上記エラーが発生
npm install -g slash => 上記エラーが発生
npm install -g npm => 上記エラーが発生

環境

• macOS Catalina 10.15.3
• npm version 6.12.1