Can't install TypeScript on MacOS - Terminal Error

Question

I have Visual Studio Code on my Mac and want to install TypeScript for Angular. I already previously installed Node.js or Git I think. This command from the TypeScript website should install TypeScript if it's run in the Mac Terminal, but it doesn't:

npm install -g typescript

If I paste it in the Terminal and press enter, this Error-code appears in the Terminal: (What is the problem? I really don't get it and have no clue about the terminal, I'm not a computer pro. Would be a big help if you have tips in easy words for beginners. Thanks!!)

MacBook-Pro:~ Max$ npm install -g typescript
npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules
npm ERR! path /usr/local/lib/node_modules
npm ERR! code EACCES
npm ERR! errno -13
npm ERR! syscall access
npm ERR! Error: EACCES: permission denied, access '/usr/local/lib/node_modules'
npm ERR!  { [Error: EACCES: permission denied, access '/usr/local/lib/node_modules']
npm ERR!   stack:
npm ERR!    'Error: EACCES: permission denied, access \'/usr/local/lib/node_modules\'',
npm ERR!   errno: -13,
npm ERR!   code: 'EACCES',
npm ERR!   syscall: 'access',
npm ERR!   path: '/usr/local/lib/node_modules' }
npm ERR! 
npm ERR! The operation was rejected by your operating system.
npm ERR! It is likely you do not have the permissions to access this file as the current user
npm ERR! 
npm ERR! If you believe this might be a permissions issue, please double-check the
npm ERR! permissions of the file and its containing directories, or try running
npm ERR! the command again as root/Administrator (though this is not recommended).

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/Max/.npm/_logs/2018-06-30T14_50_35_633Z-debug.log
MacBook-Pro:~ Max$ clear

    MacBook-Pro:~ Max$ npm install -g typescript
    npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules
    npm ERR! path /usr/local/lib/node_modules
    npm ERR! code EACCES
    npm ERR! errno -13
    npm ERR! syscall access
    npm ERR! Error: EACCES: permission denied, access '/usr/local/lib/node_modules'
    npm ERR!  { [Error: EACCES: permission denied, access '/usr/local/lib/node_modules']
    npm ERR!   stack:
    npm ERR!    'Error: EACCES: permission denied, access \'/usr/local/lib/node_modules\'',
    npm ERR!   errno: -13,
    npm ERR!   code: 'EACCES',
    npm ERR!   syscall: 'access',
    npm ERR!   path: '/usr/local/lib/node_modules' }
    npm ERR! 
    npm ERR! The operation was rejected by your operating system.
    npm ERR! It is likely you do not have the permissions to access this file as the current user
    npm ERR! 
    npm ERR! If you believe this might be a permissions issue, please double-check the
    npm ERR! permissions of the file and its containing directories, or try running
    npm ERR! the command again as root/Administrator (though this is not recommended).

    npm ERR! A complete log of this run can be found in:
    npm ERR!     /Users/Max/.npm/_logs/2018-06-30T14_58_29_869Z-debug.log
    MacBook-Pro:~ Max$ clear

    MacBook-Pro:~ Max$ npm install -g typescript
    npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules
    npm ERR! path /usr/local/lib/node_modules
    npm ERR! code EACCES
    npm ERR! errno -13
    npm ERR! syscall access
    npm ERR! Error: EACCES: permission denied, access '/usr/local/lib/node_modules'
    npm ERR!  { [Error: EACCES: permission denied, access '/usr/local/lib/node_modules']
    npm ERR!   stack:
    npm ERR!    'Error: EACCES: permission denied, access \'/usr/local/lib/node_modules\'',
    npm ERR!   errno: -13,
    npm ERR!   code: 'EACCES',
    npm ERR!   syscall: 'access',
    npm ERR!   path: '/usr/local/lib/node_modules' }
    npm ERR! 
    npm ERR! The operation was rejected by your operating system.
    npm ERR! It is likely you do not have the permissions to access this file as the current user
    npm ERR! 
    npm ERR! If you believe this might be a permissions issue, please double-check the
    npm ERR! permissions of the file and its containing directories, or try running
    npm ERR! the command again as root/Administrator (though this is not recommended).

Answer 1

npm WARN checkPermissions Missing write access to /usr/local/lib/node_modules

means you need permissions to download to that location, the reason it requires root privileges is likely because you installed nodejs/npm with root privileges.

sudo npm install -g typescript

then type in your password