Gitbook-cli install error TypeError: cb.apply is not a function inside graceful-fs

When executing any gitbook command in the terminal, the following error is thrown:

/home/travis/.nvm/versions/node/v12.18.3/lib/node_modules/gitbook-cli/node_modules/npm/node_modules/graceful-fs/polyfills.js:287
      if (cb) cb.apply(this, arguments)
                 ^
TypeError: cb.apply is not a function
    at /home/travis/.nvm/versions/node/v12.18.3/lib/node_modules/gitbook-cli/node_modules/npm/node_modules/graceful-fs/polyfills.js:287:18
    at FSReqCallback.oncomplete (fs.js:169:5)

NOTE: This does not happen in node version v12.18.2 and is still happening in version v14.6.0

The gitbook-cli seems to not be working right now, failing because of their outdated graceful-fs dependency.

Any ideas how to fix this?

The issue was originally a problem inside graceful-fs but they solved it in this commit I believe.

The problem is that GitBook is still using outdated dependencies that pull in versions of graceful-fs without the fix.

The solution I found was to update graceful-fs inside gitbook like this:

If you've installed gitbook globally by doing npm install -g gitbook-cli then your path in macOS should be something like /usr/local/lib/node_modules/gitbook-cli/node_modules/npm/node_modules. Your path may differ depending on your OS or installation location.

Run this:

cd /usr/local/lib/node_modules/gitbook-cli/node_modules/npm/node_modules/
npm install graceful-fs@latest --save

Then try installing GitBook. It should have fixed the installing problem.