Fix invalid arg type (#3978)

* default to `tailwind.css` file when no input is given

* skip undefined files

* update forgotten test fixtures

Author: RobinMalfait

__tests__/fixtures/tailwind-output-flagged.css

@@ -1,4 +1,4 @@
-/*! tailwindcss v2.0.4 | MIT License | https://tailwindcss.com */
+/*! tailwindcss v2.1.0 | MIT License | https://tailwindcss.com */
 
 /*! modern-normalize v1.0.0 | MIT License | https://github.com/sindresorhus/modern-normalize */
 

__tests__/fixtures/tailwind-output-important.css

@@ -1,4 +1,4 @@
-/*! tailwindcss v2.0.4 | MIT License | https://tailwindcss.com */
+/*! tailwindcss v2.1.0 | MIT License | https://tailwindcss.com */
 
 /*! modern-normalize v1.0.0 | MIT License | https://github.com/sindresorhus/modern-normalize */
 

__tests__/fixtures/tailwind-output-no-color-opacity.css

@@ -1,4 +1,4 @@
-/*! tailwindcss v2.0.4 | MIT License | https://tailwindcss.com */
+/*! tailwindcss v2.1.0 | MIT License | https://tailwindcss.com */
 
 /*! modern-normalize v1.0.0 | MIT License | https://github.com/sindresorhus/modern-normalize */
 

__tests__/fixtures/tailwind-output.css

@@ -1,4 +1,4 @@
-/*! tailwindcss v2.0.4 | MIT License | https://tailwindcss.com */
+/*! tailwindcss v2.1.0 | MIT License | https://tailwindcss.com */
 
 /*! modern-normalize v1.0.0 | MIT License | https://github.com/sindresorhus/modern-normalize */
 

jit/lib/setupContext.js

@@ -227,6 +227,8 @@ function trackModified(files) {
   let changed = false
 
   for (let file of files) {
+    if (!file) continue
+
     let pathname = url.parse(file).pathname
     let newModified = fs.statSync(decodeURIComponent(pathname)).mtimeMs
 

src/cli/compile.js

@@ -1,3 +1,4 @@
+import path from 'path'
 import postcss from 'postcss'
 
 import * as utils from './utils'
@@ -29,15 +30,15 @@ export default function compile(options = {}) {
   const css = config.inputFile
     ? utils.readFile(config.inputFile)
     : `
-    @tailwind base;
-    @tailwind components;
-    @tailwind utilities;
-  `
+      @tailwind base;
+      @tailwind components;
+      @tailwind utilities;
+    `
 
   return new Promise((resolve, reject) => {
     postcss(config.plugins)
       .process(css, {
-        from: config.inputFile,
+        from: config.inputFile || path.resolve(__dirname, '../../tailwind.css'),
         to: config.outputFile,
       })
       .then(resolve)