How to get a dependency of another dependency?

Question

I have a package (babel-preset-es2015-webpack) with dependency babel-preset-es2015. babel-preset-es2015 have dependency babel-plugin-transform-es2015-modules-commonjs.

How do I require babel-plugin-transform-es2015-modules-commonjs in a way to make sure that it is the same package that my babel-present-es2015 dependency is using?

Simply doing:

require('babel-plugin-transform-es2015-modules-commonjs');

Will work in NPM3 setup (assuming there are no other dependencies that require a different version of babel-plugin-transform-es2015-modules-commonjs), but will not work in NPM2.

Answer 1

If you do not want to use shrinkwrap as noted by @Nocturno, you can also simply require the specific path to the dependency:

require('<path-to-node_modules>/babel-preset-es2015-webpack/node_modules/babel-plugin-transform-es2015-modules-commonjs');

Never used the plugins myself, but something like the above should work.

Another option is to lock down babel-preset-es2015-webpack to a specific version, then determine what version of babel-plugin-transform-es2015-modules-commonjs is listed in it's package.json and add it to your package.json. Then you can use the require('babel-plugin-transform-es2015-modules-commonjs'); method in NPM2 and NPM3.