make it node 12 compatible

.github/workflows/main.yml

@@ -0,0 +1,39 @@
+name: CI
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [12.x, 15.x]
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Use Node ${{ matrix.node-version }}
+        uses: actions/setup-node@v2
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - name: Use cached node_modules
+        id: cache
+        uses: actions/cache@v2
+        with:
+          path: node_modules
+          key: nodeModules-${{ hashFiles('**/package-lock.json') }}-${{ matrix.node-version }}
+          restore-keys: |
+            nodeModules-
+
+      - name: Install dependencies
+        if: steps.cache.outputs.cache-hit != 'true'
+        run: npm install
+        env:
+          CI: true
+
+      - name: Test
+        run: npm run test -- --coverage
+        env:
+          CI: true

src/corePlugins/ringWidth.js

@@ -1,6 +1,5 @@
 const dlv = require('dlv')
 const nameClass = require('tailwindcss/lib/util/nameClass').default
-const transformThemeValue = require('tailwindcss/lib/util/transformThemeValue').default
 const toRgba = require('tailwindcss/lib/util/withAlphaVariable').toRgba
 const { asLength } = require('../pluginUtils')
 
@@ -20,8 +19,8 @@ module.exports = function ({ addBase, matchUtilities, addUtilities, jit: { theme
   let ringReset = {
     '*': {
       '--tw-ring-inset': 'var(--tw-empty,/*!*/ /*!*/)',
-      '--tw-ring-offset-width': theme.ringOffsetWidth?.DEFAULT ?? '0px',
-      '--tw-ring-offset-color': theme.ringOffsetColor?.DEFAULT ?? '#fff',
+      '--tw-ring-offset-width': dlv(theme, ['ringOffsetWidth', 'DEFAULT'], '0px'),
+      '--tw-ring-offset-color': dlv(theme, ['ringOffsetColor', 'DEFAULT'], '#fff'),
       '--tw-ring-color': ringColorDefault,
       '--tw-ring-offset-shadow': '0 0 #0000',
       '--tw-ring-shadow': '0 0 #0000',

src/lib/setupContext.js

@@ -153,7 +153,7 @@ function getTailwindConfig(configOrPath) {
 
   if (userConfigPath !== null) {
     let [prevConfig, prevModified = -Infinity, prevConfigHash] =
-      configPathCache.get(userConfigPath) ?? []
+      configPathCache.get(userConfigPath) || []
     let modified = fs.statSync(userConfigPath).mtimeMs
 
     // It hasn't changed (based on timestamp)