From a11f4644861616f7d0929e62ae9833e795dd8649 Mon Sep 17 00:00:00 2001
From: Charles Lyding <19598772+clydin@users.noreply.github.com>
Date: Tue, 20 Apr 2021 09:56:15 -0400
Subject: [PATCH] fix(@angular-devkit/build-angular): set Tailwind CSS mode
 when using Tailwind

Tailwind now suppports an environment variable named `TAILWIND_MODE` with possible values of `build` and `watch`. If the variable has not been set, the tooling will now set the variable based on the builder's `watch` option.

(cherry picked from commit 2ac73c75e7c88aa26736423e5b26c69a426c5394)
---
 .../angular_devkit/build_angular/src/webpack/configs/styles.ts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/packages/angular_devkit/build_angular/src/webpack/configs/styles.ts b/packages/angular_devkit/build_angular/src/webpack/configs/styles.ts
index c789d5505df8..1af53b2b913a 100644
--- a/packages/angular_devkit/build_angular/src/webpack/configs/styles.ts
+++ b/packages/angular_devkit/build_angular/src/webpack/configs/styles.ts
@@ -148,6 +148,9 @@ export function getStylesConfig(wco: WebpackConfigOptions): webpack.Configuratio
       );
     }
     if (tailwindPackagePath) {
+      if (process.env['TAILWIND_MODE'] === undefined) {
+        process.env['TAILWIND_MODE'] = buildOptions.watch ? 'watch' : 'build';
+      }
       extraPostcssPlugins.push(require(tailwindPackagePath)({ config: tailwindConfigPath }));
     }
   }