Note: These instructions only work with npm 6 or older. For a solution that works with npm 8 (or older), see Updating-npm-bundled-node-gyp.md.
Many issues are opened by users who are not running a current version of node-gyp.
npm bundles its own, internal, copy of node-gyp located at npm/node_modules, within npm's private dependencies which are separate from globally accessible packages. Therefore this internal copy of node-gyp is independent from any globally installed copy of node-gyp that
may have been installed via npm install -g node-gyp.
So npm's internal copy of node-gyp isn't stored inside global node_modules and thus isn't available for use as a standalone package. npm uses it's internal copy of node-gyp to automatically build native addons.
When you install a new version of node-gyp outside of npm, it'll go into your global node_modules, but not under the npm/node_modules (where internal copy of node-gyp is stored). So it will get into your $PATH and you will be able to use this globally installed version (but not internal node-gyp of npm) as any other globally installed package.
The catch is that npm won't use global version unless you tell it to, it'll keep on using the internal one. You need to instruct it to by setting the node_gyp config variable (which goes into your ~/.npmrc). You do this by running the npm config set command as below. Then npm will use the command in the path you supply whenever it needs to build a native addon.
Important: You also need to remember to unset this when you upgrade npm with a newer version of node-gyp, or you have to manually keep your globally installed node-gyp to date. See "Undo" below.
npm install --global node-gyp@latest
npm config set node_gyp $(npm prefix -g)/lib/node_modules/node-gyp/bin/node-gyp.js
sudo may be required for the first command if you get a permission error.
npm install --global node-gyp@latest
for /f "delims=" %P in ('npm prefix -g') do npm config set node_gyp "%P\node_modules\node-gyp\bin\node-gyp.js"
npm install --global node-gyp@latest
npm prefix -g | % {npm config set node_gyp "$_\node_modules\node-gyp\bin\node-gyp.js"}
Beware if you don't unset the node_gyp config option, npm will continue to use the globally installed version of node-gyp rather than the one it ships with, which may end up being newer.
npm config delete node_gyp
npm uninstall --global node-gyp