From cf17aee48b1427a2927d84951c75cb93a44fa10a Mon Sep 17 00:00:00 2001
From: Stephen Niedzielski <stephen@niedzielski.com>
Date: Thu, 30 Jul 2020 20:53:19 -0600
Subject: [PATCH] [build] Make the pre-commit hook optional

Add a new NPM script, `pre-commit`, which _conditionally_ invokes
`npm test`. Previously, the pre-commit hook was configured by default to
invoke `npm test`. Now it is configured explicitly to invoke the new
`pre-commit` script.

The rationale for this change is that some folks may prefer workflows
that defer all validation until CI. Supporting these workflows is a
small change, most of it documentation.

This change isn't necessary for T257647 but supports and seems like an
overall improvement to the repo regardless of whether code is built or
not.

Bug: T257647
Change-Id: I19a78e0e677026cd6887245d96e63a414397a3db
---
 README.md    | 20 ++++++++++++++++++++
 package.json |  4 +++-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 88942d8e..e5eadb7b 100644
--- a/README.md
+++ b/README.md
@@ -48,5 +48,25 @@ configurable via the configurations prefixed with `VectorDefaultSkinVersion`.
 Version preference and configuration may be overridden by the `useskinversion`
 URL query parameter.
 
+### Pre-commit tests
+
+A pre-commit hook is installed when executing `npm install`. By default, it runs
+`npm test` which is useful for automatically validating everything that can be
+in a reasonable amount of time. If you wish to defer these tests to be executed
+by continuous integration only, set the `PRE_COMMIT` environment variable to `0`:
+
+```bash
+$ export PRE_COMMIT=0
+$ git commit
+```
+
+Or more succinctly:
+
+```bash
+$ PRE_COMMIT=0 git commit
+```
+
+Skipping the pre-commit tests has no impact on Gerrit change identifier hooks.
+
 ### Hooks
 See [hooks.txt](hooks.txt).
diff --git a/package.json b/package.json
index 1ae55eb0..03c01283 100644
--- a/package.json
+++ b/package.json
@@ -14,8 +14,10 @@
 		"selenium-test": "npm -s run test:size",
 		"doc": "jsdoc -c jsdoc.json && npm run build-storybook",
 		"build-storybook": "dev-scripts/setup-storybook.sh && build-storybook --quiet --loglevel warn -o docs/ui",
-		"svgmin": "svgo --config=.svgo.yml -q -r -f resources/"
+		"svgmin": "svgo --config=.svgo.yml -q -r -f resources/",
+		"pre-commit": "[ \"${PRE_COMMIT:-1}\" -eq 0 ] || npm -s t"
 	},
+	"pre-commit": "pre-commit",
 	"devDependencies": {
 		"@babel/core": "7.7.7",
 		"@storybook/html": "5.2.8",