Esto es lo que muestra el error:

npm does not support Node.js v10.19.0
You should probably upgrade to a newer version of node as we
can't make any promises that npm will work with this version.
You can find the latest version at  https://nodejs.org/
/usr/local/lib/node_modules/npm/lib/npm.js:32
#unloaded = false
SyntaxError: Invalid or unexpected token
at Module._compile (internal/modules/cjs/loader.js:723:23)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10)
at Module.load (internal/modules/cjs/loader.js:653:32)
at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
at Function.Module._load (internal/modules/cjs/loader.js:585:3)
at Module.require (internal/modules/cjs/loader.js:692:17)
at require (internal/modules/cjs/helpers.js:25:18)
at module.exports (/usr/local/lib/node_modules/npm/lib/cli.js:22:15)
at Object. (/usr/local/lib/node_modules/npm/bin/npm-cli.js:2:25)
at Module._compile (internal/modules/cjs/loader.js:778:30)

Node.js version

10.19.0

La solución si se esta utilizando nvm es desinstalar y volver a instalar la versión nuevamente:

nvm uninstall 10
nvm install 10

Fuente:

https://github.com/nodejs/help/issues/3644