Performance improvements

lib/index.js

@@ -87,7 +87,7 @@ function chain(instance) {
       get: function() {
         return Object.keys(this.__style).reduce((acc, key) => {
           if (typeof this.__style[key] === 'number' || typeof this.__style[key] === 'string')
-            acc[key.replace(/^!/, '')] = this.__style[key]
+            acc[key.charAt(0) === '!' ? key.slice(1) : key] = this.__style[key]
           return acc
         }, {})
       }
@@ -144,12 +144,11 @@ function $media(value, style) {
   return b
 }
 
+const hasUrl = /^('|"|url\('|url\(")/i
 function $import(value) {
-  if (value && !/^('|"|url\('|url\(")/.test(value))
-    value = '"' + value + '"'
-
-  if (value)
-    insert('@import ' + value + ';', 0)
+  value && insert('@import '
+    + (hasUrl.test(value) ? value : '"' + value + '"')
+    + ';', 0)
 
   return chain(this)
 }
@@ -255,15 +254,19 @@ function short(prop) {
   return short
 }
 
+const blockEndMatch = /;(?![^("]*[)"])|\n/
+const commentsMatch = /\/\*[\s\S]*?\*\/|([^:]|^)\/\/.*(?![^("]*[)"])/g
+const propSeperator = /[ :]+/
+
 const stringToObject = memoize(string => {
   let last = ''
     , prev
 
-  return string.trim().replace(/\/\*[\s\S]*?\*\/|([^:]|^)\/\/.*(?![^("]*[)"])/g, '').split(/;(?![^("]*[)"])|\n/).reduce((acc, line) => {
+  return string.trim().replace(commentsMatch, '').split(blockEndMatch).reduce((acc, line) => {
     if (!line)
       return acc
     line = last + line.trim()
-    const [key, ...tokens] = line.replace(/[ :]+/, ' ').split(' ')
+    const [key, ...tokens] = line.replace(propSeperator, ' ').split(' ')
 
     last = line.charAt(line.length - 1) === ',' ? line : ''
     if (last)

lib/utils.js

@@ -66,20 +66,24 @@ export function assign(obj, obj2) {
   return obj
 }
 
+const hyphenSeparator = /-([a-z])/g
 export function hyphenToCamelCase(hyphen) {
-  return hyphen.slice(hyphen.charAt(0) === '-' ? 1 : 0).replace(/-([a-z])/g, function(match) {
+  return hyphen.slice(hyphen.charAt(0) === '-' ? 1 : 0).replace(hyphenSeparator, function(match) {
     return match[1].toUpperCase()
   })
 }
 
+const camelSeparator = /(\B[A-Z])/g
 export function camelCaseToHyphen(camelCase) {
-  return camelCase.replace(/(\B[A-Z])/g, '-$1').toLowerCase()
+  return camelCase.replace(camelSeparator, '-$1').toLowerCase()
 }
 
+const initialMatch = /([A-Z])/g
 export function initials(camelCase) {
-  return camelCase.charAt(0) + (camelCase.match(/([A-Z])/g) || []).join('').toLowerCase()
+  return camelCase.charAt(0) + (camelCase.match(initialMatch) || []).join('').toLowerCase()
 }
 
+const ampersandMatch = /&/g
 export function objectToRules(style, selector, suffix = '', single) {
   const base = {}
   const extra = suffix.indexOf('&') > -1 && suffix.indexOf(',') === -1 ? '' : '&'
@@ -96,7 +100,7 @@ export function objectToRules(style, selector, suffix = '', single) {
 
   if (Object.keys(base).length) {
     rules.unshift(
-      ((single || (suffix.charAt(0) === ' ') ? '' : '&') + extra + suffix).replace(/&/g, selector).trim() +
+      ((single || (suffix.charAt(0) === ' ') ? '' : '&') + extra + suffix).replace(ampersandMatch, selector).trim() +
       '{' + stylesToCss(base) + '}'
     )
   }
@@ -108,7 +112,7 @@ export const selectorSplit = /,(?=(?:(?:[^"]*"){2})*[^"]*$)/
 
 export function stylesToCss(style) {
   return Object.keys(style).reduce((acc, prop) =>
-    acc + propToString(prop.replace(/!/g, ''), style[prop])
+    acc + propToString(prop.charAt(0) === '!' ? prop.slice(1) : prop, style[prop])
   , '')
 }