Replaces "Yarn PnP" by "Yarn 2"

[arcanis]

Fixes #31

I've also enabled the Yarn 2 benchmark for the parts that were previously n/a by removing the .pnp.js where the node_modules folder would have been removed otherwise.

[arcanis]

Now that I think about it, now that the cache and the node_modules are effectively the same, the results aren't as easy to interpret 🤔 Hmm maybe the "n/a" approach was more sensible ...

[zkochan]

Might make sense to rename the columns to Yarn 1 and Yarn 2. But to be honest, why not just run the performance tests for Yarn 2 and name it "Yarn"? Why do we need to include Yarn 1 in the benchmarks?

[arcanis]

I think it's still valuable given that many people will only migrate over time. Plus, since 1.x and 2.x are quite different implementations with different tradeoffs, it gives a nice way to see the impact of the choices we made, one way or another.

[arcanis]

I'll restore the n/a, use a different color for Yarn 2.x, add the "1.x" label to the column, and maybe sort the table so that all the "caches" / "no caches" are put together - it really highlights where is 2.x faster or slower.

Btw @zkochan, what's your secret sauce for "cache / no lockfile / n_m"? I'd expect it to take at least the time needed to fetch the metadata from the registry 🤔

[zkochan]

I think that case is so fast because even though there is no lockfile near the package.json, there is still a lockfile duplicate inside node_modules/.pnpm/lock.yaml.

pnpm has two lockfiles. They have the same format. One is in the same folder in which package.json and the other one inside node_modules. This is great because after a branch switch, for instance, we just make a diff of the two lockfiles and we know what to remove or add.

[zkochan]

It would be nice to update the benchmarks to use Yarn 2. I'd love to see how pnpm v5 performs compared to it.

[SgtPooki]

Anyone working on getting this merged?

[zkochan]

I don't think so because Yarn now maintains its own benchmarks: https://yarnpkg.com/benchmarks

I think I would prefer to keep only benchmarks that compare non-PnP package managers in this repo: npm7, pnpm, and Yarn2 with node-linker=node-modules

and we can add a link to Yarn benchmarks to see how PnP performs compared to pnpm.