Adds support for ESM tailwind.config.js files

.eslintignore

@@ -2,3 +2,4 @@
 /docs
 /__tests__/fixtures/cli-utils.js
 /stubs/*
+/src/util/requireOrImportConfig.js

package.json

@@ -94,6 +94,9 @@
           }
         }
       ]
+    ],
+    "exclude": [
+      "src/util/requireOrImportConfig.js"
     ]
   },
   "jest": {

src/index.js

@@ -9,6 +9,7 @@ import processTailwindFeatures from './processTailwindFeatures'
 import formatCSS from './lib/formatCSS'
 import resolveConfig from './util/resolveConfig'
 import getAllConfigs from './util/getAllConfigs'
+import requireOrImportConfig from './util/requireOrImportConfig'
 import { supportedConfigFiles } from './constants'
 import defaultConfig from '../stubs/defaultConfig.stub.js'
 
@@ -45,7 +46,7 @@ function resolveConfigPath(filePath) {
   return undefined
 }
 
-const getConfigFunction = (config) => () => {
+const getConfigFunction = (config) => async () => {
   if (_.isUndefined(config)) {
     return resolveConfig([...getAllConfigs(defaultConfig)])
   }
@@ -59,7 +60,9 @@ const getConfigFunction = (config) => () => {
     }
   }
 
-  const configObject = _.isObject(config) ? _.get(config, 'config', config) : require(config)
+  const configObject = _.isObject(config)
+    ? _.get(config, 'config', config)
+    : await requireOrImportConfig(config)
 
   return resolveConfig([...getAllConfigs(configObject)])
 }

src/processTailwindFeatures.js

@@ -25,8 +25,8 @@ let processedPlugins = null
 let getProcessedPlugins = null
 
 export default function (getConfig) {
-  return function (css) {
-    const config = getConfig()
+  return async function (css) {
+    const config = await getConfig()
     const configChanged = hash(previousConfig) !== hash(config)
     previousConfig = config
 

src/util/requireOrImportConfig.js

@@ -0,0 +1,26 @@
+"use strict";
+
+// Node v12.17+ exposes `import` within CJS files
+// in order to `require` ESM files.
+
+// This file is intentionally excluded from `babel` (and `eslint`)
+// to avoid transpiling away the `import` statement
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+
+exports.default = requireOrImportConfig;
+
+function requireOrImportConfig(config) {
+  try {
+    return require(config)
+  } catch (e) {
+    if (e.code === 'ERR_REQUIRE_ESM') {
+      try {
+        return import(config).then(mdl => mdl.default)
+      } catch (e) {}
+    }
+  }
+  return null;
+}