From c7061e922894ed8690c0401a66d325e59ab7d54a Mon Sep 17 00:00:00 2001
From: Adam Wathan <adam.wathan@gmail.com>
Date: Mon, 6 Nov 2017 10:32:17 -0500
Subject: [PATCH] Support default values in config function

Also add a bunch of tests, seems probably wise :)
---
 __tests__/configFunction.test.js     | 82 ++++++++++++++++++++++++++++
 src/lib/evaluateTailwindFunctions.js |  4 +-
 2 files changed, 84 insertions(+), 2 deletions(-)
 create mode 100644 __tests__/configFunction.test.js

diff --git a/__tests__/configFunction.test.js b/__tests__/configFunction.test.js
new file mode 100644
index 000000000..11f93876a
--- /dev/null
+++ b/__tests__/configFunction.test.js
@@ -0,0 +1,82 @@
+import postcss from 'postcss'
+import plugin from '../src/lib/evaluateTailwindFunctions'
+
+function run(input, opts = {}) {
+  return postcss([plugin(() => opts)]).process(input)
+}
+
+test("it looks up values in the config using dot notation", () => {
+  const input = `
+    .banana { color: config('colors.yellow'); }
+  `
+
+  const output = `
+    .banana { color: #f7cc50; }
+  `
+
+  return run(input, {
+    colors: {
+      yellow: '#f7cc50',
+    }
+  }).then(result => {
+    expect(result.css).toEqual(output)
+    expect(result.warnings().length).toBe(0)
+  })
+})
+
+test("quotes are optional around the lookup path", () => {
+  const input = `
+    .banana { color: config(colors.yellow); }
+  `
+
+  const output = `
+    .banana { color: #f7cc50; }
+  `
+
+  return run(input, {
+    colors: {
+      yellow: '#f7cc50',
+    }
+  }).then(result => {
+    expect(result.css).toEqual(output)
+    expect(result.warnings().length).toBe(0)
+  })
+})
+
+test("a default value can be provided", () => {
+  const input = `
+    .cookieMonster { color: config('colors.blue', #0000ff); }
+  `
+
+  const output = `
+    .cookieMonster { color: #0000ff; }
+  `
+
+  return run(input, {
+    colors: {
+      yellow: '#f7cc50',
+    }
+  }).then(result => {
+    expect(result.css).toEqual(output)
+    expect(result.warnings().length).toBe(0)
+  })
+})
+
+test("quotes are preserved around default values", () => {
+  const input = `
+    .heading { font-family: config('fonts.sans', "Helvetica Neue"); }
+  `
+
+  const output = `
+    .heading { font-family: "Helvetica Neue"; }
+  `
+
+  return run(input, {
+    fonts: {
+      serif: "Constantia",
+    }
+  }).then(result => {
+    expect(result.css).toEqual(output)
+    expect(result.warnings().length).toBe(0)
+  })
+})
diff --git a/src/lib/evaluateTailwindFunctions.js b/src/lib/evaluateTailwindFunctions.js
index 3b2ab3486..2e00ed9c1 100644
--- a/src/lib/evaluateTailwindFunctions.js
+++ b/src/lib/evaluateTailwindFunctions.js
@@ -6,8 +6,8 @@ export default function(config) {
 
   return functions({
     functions: {
-      config: function (path) {
-        return _.get(options, _.trim(path, `'"`))
+      config: function (path, defaultValue) {
+        return _.get(options, _.trim(path, `'"`), defaultValue)
       }
     }
   })