From 10be05a16715e88e42fdb03b34e744bd05ed5702 Mon Sep 17 00:00:00 2001
From: Adam Wathan <adam.wathan@gmail.com>
Date: Tue, 6 Mar 2018 14:08:30 -0500
Subject: [PATCH] Get object style parsing working without the insanity

---
 __tests__/parseObjectStyles.test.js | 214 +++++++++++++++++++++++-----
 src/util/parseObjectStyles.js       |  68 +--------
 2 files changed, 184 insertions(+), 98 deletions(-)

diff --git a/__tests__/parseObjectStyles.test.js b/__tests__/parseObjectStyles.test.js
index 5555d9dfc..39e88bfc6 100644
--- a/__tests__/parseObjectStyles.test.js
+++ b/__tests__/parseObjectStyles.test.js
@@ -1,6 +1,4 @@
-import _ from 'lodash'
 import parseObjectStyles from '../src/util/parseObjectStyles'
-import cxs from 'cxs'
 import postcss from 'postcss'
 
 function css(nodes) {
@@ -16,7 +14,7 @@ test('it parses simple single class definitions', () => {
     },
   })
 
-  expect(result).toMatchCss(`
+  expect(css(result)).toMatchCss(`
     .foobar {
       background-color: red;
       color: white;
@@ -38,7 +36,7 @@ test('it parses multiple class definitions', () => {
     },
   })
 
-  expect(result).toMatchCss(`
+  expect(css(result)).toMatchCss(`
     .foo {
       background-color: red;
       color: white;
@@ -66,17 +64,35 @@ test('it parses nested pseudo-selectors', () => {
     },
   })
 
-  expect(result).toMatchCss(`
+  expect(css(result)).toMatchCss(`
     .foo {
       background-color: red;
       color: white;
-      padding: 1rem
+      padding: 1rem;
     }
     .foo:hover {
-      background-color: orange
+      background-color: orange;
     }
     .foo:focus {
-      background-color: blue
+      background-color: blue;
+    }
+  `)
+})
+
+test('it parses top-level media queries', () => {
+  const result = parseObjectStyles({
+    '@media (min-width: 200px)': {
+      '.foo': {
+        backgroundColor: 'orange',
+      },
+    },
+  })
+
+  expect(css(result)).toMatchCss(`
+    @media (min-width: 200px) {
+      .foo {
+        background-color: orange
+      }
     }
   `)
 })
@@ -93,44 +109,168 @@ test('it parses nested media queries', () => {
     },
   })
 
-  expect(result).toMatchCss(`
+  expect(css(result)).toMatchCss(`
     .foo {
       background-color: red;
       color: white;
-      padding: 1rem
+      padding: 1rem;
     }
     @media (min-width: 200px) {
       .foo {
-        background-color: orange
+        background-color: orange;
       }
     }
   `)
 })
 
-// test('it parses pseudo-selectors in nested media queries', () => {
-//   const result = parseObjectStyles({
-//     '.foo': {
-//       backgroundColor: 'red',
-//       color: 'white',
-//       padding: '1rem',
-//       ':hover': {
-//         '@media (min-width: 200px)': {
-//           backgroundColor: 'orange',
-//         }
-//       },
-//     },
-//   })
+test('it parses pseudo-selectors in nested media queries', () => {
+  const result = parseObjectStyles({
+    '.foo': {
+      backgroundColor: 'red',
+      color: 'white',
+      padding: '1rem',
+      ':hover': {
+        '@media (min-width: 200px)': {
+          backgroundColor: 'orange',
+        },
+      },
+    },
+  })
 
-//   expect(result).toMatchCss(`
-//     .foo {
-//       background-color: red;
-//       color: white;
-//       padding: 1rem
-//     }
-//     @media (min-width: 200px) {
-//       .foo:hover {
-//         background-color: orange
-//       }
-//     }
-//   `)
-// })
+  expect(css(result)).toMatchCss(`
+    .foo {
+      background-color: red;
+      color: white;
+      padding: 1rem;
+    }
+    @media (min-width: 200px) {
+      .foo:hover {
+        background-color: orange;
+      }
+    }
+  `)
+})
+
+test('it parses descendant selectors', () => {
+  const result = parseObjectStyles({
+    '.foo': {
+      backgroundColor: 'red',
+      color: 'white',
+      padding: '1rem',
+      '.bar': {
+        backgroundColor: 'orange',
+      },
+    },
+  })
+
+  expect(css(result)).toMatchCss(`
+    .foo {
+      background-color: red;
+      color: white;
+      padding: 1rem;
+    }
+    .foo .bar {
+      background-color: orange;
+    }
+  `)
+})
+
+test('it parses nested multi-class selectors', () => {
+  const result = parseObjectStyles({
+    '.foo': {
+      backgroundColor: 'red',
+      color: 'white',
+      padding: '1rem',
+      '&.bar': {
+        backgroundColor: 'orange',
+      },
+    },
+  })
+
+  expect(css(result)).toMatchCss(`
+    .foo {
+      background-color: red;
+      color: white;
+      padding: 1rem;
+    }
+    .foo.bar {
+      background-color: orange;
+    }
+  `)
+})
+
+test('it parses nested multi-class selectors in media queries', () => {
+  const result = parseObjectStyles({
+    '.foo': {
+      backgroundColor: 'red',
+      color: 'white',
+      padding: '1rem',
+      '@media (min-width: 200px)': {
+        '&.bar': {
+          backgroundColor: 'orange',
+        },
+      },
+    },
+  })
+
+  expect(css(result)).toMatchCss(`
+    .foo {
+      background-color: red;
+      color: white;
+      padding: 1rem;
+    }
+    @media (min-width: 200px) {
+      .foo.bar {
+        background-color: orange;
+      }
+    }
+  `)
+})
+
+test('it strips empty selectors when nesting', () => {
+  const result = parseObjectStyles({
+    '.foo': {
+      '.bar': {
+        backgroundColor: 'orange',
+      },
+    },
+  })
+
+  expect(css(result)).toMatchCss(`
+    .foo .bar {
+      background-color: orange
+    }
+  `)
+})
+
+test('it can parse an array of styles', () => {
+  const result = parseObjectStyles([
+    {
+      '.foo': {
+        backgroundColor: 'orange',
+      },
+    },
+    {
+      '.bar': {
+        backgroundColor: 'red',
+      },
+    },
+    {
+      '.foo': {
+        backgroundColor: 'blue',
+      },
+    },
+  ])
+
+  expect(css(result)).toMatchCss(`
+    .foo {
+      background-color: orange
+    }
+    .bar {
+      background-color: red
+    }
+    .foo {
+      background-color: blue
+    }
+  `)
+})
diff --git a/src/util/parseObjectStyles.js b/src/util/parseObjectStyles.js
index 9fd9a3755..8ecff5cb0 100644
--- a/src/util/parseObjectStyles.js
+++ b/src/util/parseObjectStyles.js
@@ -1,69 +1,15 @@
 import _ from 'lodash'
 import postcss from 'postcss'
+import postcssNested from 'postcss-nested'
+import postcssJs from 'postcss-js'
 
-const hyph = s => s.replace(/[A-Z]|^ms/g, '-$&').toLowerCase()
-const mx = (rule, media) => media ? `${media}{${rule}}` : rule
-const noAnd = s => s.replace(/&/g, '')
-const createDeclaration = (key, value) => hyph(key) + ':' + value
-const createRule = ({
-  className,
-  child,
-  media,
-  declarations
-}) => mx(`${className + child}{${declarations.join(';')}}`, media)
-
-const parseRules = (obj, child = '', media) => {
-  const rules = []
-  const declarations = []
-
-  for (let key in obj) {
-    const value = obj[key]
-
-    if (value === null) continue
-
-    if (typeof value === 'object') {
-      const _media = /^@/.test(key) ? key : null
-      const _child = _media ? child : child + noAnd(key)
-      parseRules(value, _child, _media)
-        .forEach(r => rules.push(r))
-      continue
-    }
-
-    const dec = createDeclaration(key, value)
-    declarations.push(dec)
-  }
-
-  rules.unshift({
-    media,
-    child,
-    declarations
-  })
-
-  return rules
-}
-
-const parse = (selector, obj) => {
-  const rules = parseRules(obj)
-
-  console.log(rules)
-
-  return rules.map(rule => {
-    const className = selector
-    const ruleset = createRule(Object.assign(rule, { className }))
-    return ruleset
-  })
-}
-
-function parseObjectStyles(styles) {
+export default function parseObjectStyles(styles) {
   if (!Array.isArray(styles)) {
     return parseObjectStyles([styles])
   }
 
-  return _.flatMap(styles, (style) => {
-    return _.flatMap(style, (declarations, selector) => {
-      return parse(selector, declarations)
-    })
-  }).join('')
+  return _.flatMap(
+    styles,
+    style => postcss([postcssNested]).process(style, { parser: postcssJs }).root.nodes
+  )
 }
-
-export default parseObjectStyles