Build package in prepack instead of prepublish

[Methuselah96]

From Yarn docs about lifecycle scripts:

Note about yarn pack: Although rarely called directly, yarn pack is a crucial part of Yarn. Each time Yarn has to fetch a dependency from a "raw" source (such as a Git repository), it will automatically run yarn install and yarn pack on it to know which are the files to use.

prepack is the lifecycle script called before each call to yarn pack. This is typically the place where you'll want to put scripts that build a package - such as transpiling its source.

prepublish is called before yarn npm publish and similar commands (even before the package has been packed). This is the place where you'll want to check that the project is in an ok state. Because it's only called on prepublish, the prepublish hook shouldn't have side effects. In particular don't transpile the package sources in prepublish, as people consuming directly your repository (such as through the git: protocol) wouldn't be able to use your project.

I have found this change to be helpful when trying to install Redux using the Git protocol in order to test out changes on a specific branch.

prepack is run as part of npm/yarn publish so this change should hopefully not change anything about publishing.

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit 64df556:

Sandbox	Source
Vanilla	Configuration
Vanilla Typescript	Configuration

[timdorr]

To be honest, I really hate these hook scripts anyways. We should just have an automated build and publishing process (we have this on React Router, for instance).

But for now, this at least alleviates some of the hassle.

[markerikson]

fwiw I've always published locally, first using np, now using release-it.