Merge pull request #903 from CvX/theme-deep-function-values

Allow accessing deep paths with function values via theme helper

__tests__/resolveConfig.test.js

@@ -830,6 +830,59 @@ test('the theme function can resolve function values', () => {
   })
 })
 
+test('the theme function can resolve deep function values', () => {
+  const userConfig = {
+    theme: {
+      minWidth: theme => ({
+        '1/3': theme('width.1/3'),
+      }),
+    },
+  }
+
+  const defaultConfig = {
+    prefix: '-',
+    important: false,
+    separator: ':',
+    theme: {
+      spacing: {
+        '0': '0',
+      },
+      width: theme => ({
+        ...theme('spacing'),
+        '1/3': '33.33333%',
+      }),
+    },
+    variants: {
+      backgroundColor: ['responsive', 'hover', 'focus'],
+      borderColor: ['responsive', 'hover', 'focus'],
+    },
+  }
+
+  const result = resolveConfig([userConfig, defaultConfig])
+
+  expect(result).toEqual({
+    prefix: '-',
+    important: false,
+    separator: ':',
+    theme: {
+      spacing: {
+        '0': '0',
+      },
+      width: {
+        '0': '0',
+        '1/3': '33.33333%',
+      },
+      minWidth: {
+        '1/3': '33.33333%',
+      },
+    },
+    variants: {
+      backgroundColor: ['responsive', 'hover', 'focus'],
+      borderColor: ['responsive', 'hover', 'focus'],
+    },
+  })
+})
+
 test('theme values in the extend section are lazily evaluated', () => {
   const userConfig = {
     theme: {

src/util/resolveConfig.js

@@ -2,7 +2,7 @@ import mergeWith from 'lodash/mergeWith'
 import isFunction from 'lodash/isFunction'
 import defaults from 'lodash/defaults'
 import map from 'lodash/map'
-import get from 'lodash/get'
+import toPath from 'lodash/toPath'
 
 const configUtils = {
   negative(scale) {
@@ -40,8 +40,17 @@ function mergeExtensions({ extend, ...theme }) {
 
 function resolveFunctionKeys(object) {
   const resolveThemePath = (key, defaultValue) => {
-    const val = get(object, key, defaultValue)
-    return isFunction(val) ? val(resolveThemePath) : val
+    const path = toPath(key)
+
+    let index = 0
+    let val = object
+
+    while (val !== undefined && val !== null && index < path.length) {
+      val = val[path[index++]]
+      val = isFunction(val) ? val(resolveThemePath) : val
+    }
+
+    return val === undefined ? defaultValue : val
   }
 
   return Object.keys(object).reduce((resolved, key) => {