cherry-pick
v0.5.0
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🍒⛏📦 Build tool to generate proxy directories.
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cherry-pick 🍒⛏📦
Build tool to generate proxy directories with package.json
files such as this:
{
"name": "redux-saga/effects",
"private": true,
"main": "../lib/effects.js",
"module": "../es/effects.js"
}
Why?
When it comes to "main" entry points of our libraries we have an easy way for
supporting both CJS & ESM files with respectively "main"
and "module"
fields
in package.json
. This allows resolution algorithms to chose a file with the
best format automatically. However if we have multiple files in a package and
we want all of them to be importable we often suggest to users doing it like
this:
import module from "package/lib/module";
There are problems with this approach:
- it is often encouraging people to import files authored in CJS format, which
if produced with tools like
babel
has i.e. interop helper functions deoptimizing imported file size when comparing to the same file authored in ESM format. Alsowebpack
just bails out on CJS files when trying to optimize your application size with techniques such as tree-shaking & scope hoisting (a.k.a module concatenation). - it is exposing internal directory structure to the user. Why
lib
is in the requested path? If you ship both CJS & ESM directories tonpm
and if users would like to import appropriate file depending on the tool they are "forced" to remember this and switch between importing the same thing with paths likepackage/lib/module
andpackage/es/module
. This is a mental overhead that can be avoided.
This technique was also described by me in more details in this article.
CLI Options
default
cherry-pick [input-dir]
Create proxy directories
Commands:
cherry-pick [input-dir] Create proxy directories [default]
cherry-pick clean [input-dir] Cleanup generated directories
Options:
--help, -h Show help [boolean]
--version, -v Show version number [boolean]
--cjs-dir [default: "lib"]
--esm-dir [default: "es"]
--types-dir
--cwd [default: "."]
--input-dir [default: "src"]
clean
cherry-pick clean [input-dir]
Cleanup generated directories
Options:
--help, -h Show help [boolean]
--version, -v Show version number [boolean]
--cwd [default: "."]
--input-dir [default: "src"]
JS API
cherry-pick
exports a default
method which creates proxy directories and
clean
which removes them. Both accepts the same options as corresponding CLI
commands, only they are camelCased.
const { default: cherryPick, clean } = require("cherry-pick");
cherryPick({ inputDir: "source" })
.then(cherryPicked =>
console.log(`Created proxy directories: ${cherryPicked.join(", ")}`)
)
.then(() => clean({ inputDir: "source" }))
.then(removed =>
console.log(`Removed proxy directories: ${Removed.join(", ")}`)
);