Add Load And Use Env Var In Node Script as a JavaScript TIL

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
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@@ -465,6 +465,7 @@ _1379 TILs and counting..._
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 - [Link A JavaScript Package Locally](javascript/link-a-javascript-package-locally.md)
 - [List Top-Level NPM Dependencies](javascript/list-top-level-npm-dependencies.md)
+- [Load And Use Env Var In Node Script](javascript/load-and-use-env-var-in-node-script.md)
 - [Make The Browser Editable With Design Mode](javascript/make-the-browser-editable-with-design-mode.md)
 - [Matching A Computed Property In Function Args](javascript/matching-a-computed-property-in-function-args.md)
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javascript/load-and-use-env-var-in-node-script.md

@@ -0,0 +1,43 @@
+# Load And Use Env Var In Node Script
+
+The node scripts defined under `scripts` in a `package.json` file can be used
+to do all sorts of handy development tasks for a project.
+
+There are times where those scripts would be even more useful if they had
+access to environment variables specified in the project's `.env` files.
+
+With the help of [`dotenv-cli`](https://github.com/venthur/dotenv-cli) and
+[`cross-var`](https://github.com/elijahmanor/cross-var), we can load in and
+reference the project's env vars.
+
+As an example, let's say our `.env` file has a `DATABASE_URL`:
+
+```
+DATABASE_URL="postgresql://postgres:postgres@localhost:5432/postgres"
+```
+
+We can create a node script in `package.json` that accesses that value like so:
+
+```json
+{
+  "scripts": {
+    "db:url": "dotenv cross-var -- echo \"%DATABASE_URL%\""
+  }
+}
+```
+
+Running that command will echo out the value:
+
+```bash
+❯ npm run db:url
+
+> db:url
+> dotenv cross-var -- echo "%DATABASE_URL%"
+
+postgresql://postgres:postgres@localhost:9876/postgres
+```
+
+You could do something more useful with that value like open a `psql`
+connection to that local database.
+
+[source](https://www.genui.com/resources/env-variables-json)