LOOSE-ENVIFY(1)

💖 loose-envify — the manual page, bestie edition 💖

okay so. this is loose-envify, from the loose-envify man page (1). yes the name is a little goofy, no we're not changing it. sit down, grab a strawberry 🍓, and let me tell you about the little transpiler that could.

---

✨ NAME ✨

loose-envify — swap your Node.js environment variables out for plain old strings. that's it. that's the whole job. and it eats. 💅

---

🎀 SYNOPSIS 🎀

loose-envify <javascript_source_file.js>

that's the whole vibe. one file in, transformed source out.

---

🦋 DESCRIPTION 🦋

so what's actually happening here, fr fr? loose-envify performs a Javascript source-to-source transformation — aka transpiling, if you wanna sound fancy at the function 🧚 — and what it does is efficiently replace those Node.js process.env environment variables with plain strings. like, actual literal string values, just sitting there in your code.

why do we care?? because it makes those environment variable checks faster and sooooo much easier to optimize out. the way that a bundler or minifier can just look at a plain string comparison and go "girl, that's dead code, bye" instead of having to reason about process.env at runtime? iconic. main character energy. periodt.

---

🌸 EXAMPLES 🌸

let's see it in action because honestly this is the part that makes it click. take this source code:

if (process.env.NODE_ENV === "development") {
  console.log('development only')
}

run it through loose-envify, like:

loose-envify index.js > bundle.js

and if your NODE_ENV is set to production, you get this out the other side:

if ("production" === "development") {
  console.log('development only')
}

"production" === "development" is literally never true, so when you push that through a minifier, the whole thing gets stripped out completely. gone. evaporated. no cap. 🔥

BUT. plot twist 🙈 — if you run that same script through loose-envify with NODE_ENV set to development, you instead get:

if ("development" === "development") {
  console.log('development only')
}

and now the if statement evaluates to true, so the code stays. it will not be removed. she's a keeper. 👑

so yeah — same tool, same file, two completely different bundles depending on one env var. that's the whole magic trick. ✨

---

💜 AUTHOR 💜

Andres Suarez <zertosh@gmail.com>

---

🌈 COPYRIGHT 🌈

this manual page was written by Paolo Greppi <paolo.greppi@libpf.com> for the Debian project (and may be used by others), also based on material from the envify README (https://github.com/hughsk/envify) by Hugh Kennedy <hughskennedy@gmail.com> and the envify contributors. credit where credit is due, always. 🫶

---

and that's the page! this is loose-envify v1.3.0, dated November 2022, straight from the loose-envify man page. go transpile something cute. bye bestie! 💖✨🎀