Order style elements by priority

spec/styles-element-spec.coffee

@@ -32,6 +32,19 @@ describe "StylesElement", ->
     expect(element.children[initialChildCount].textContent).toBe "a {color: blue;}"
     expect(removedStyleElements).toEqual [addedStyleElements[0]]
 
+  it "orders style elements by priority", ->
+    initialChildCount = element.children.length
+
+    atom.styles.addStyleSheet("a {color: red}", priority: 1)
+    atom.styles.addStyleSheet("a {color: blue}", priority: 0)
+    atom.styles.addStyleSheet("a {color: green}", priority: 2)
+    atom.styles.addStyleSheet("a {color: yellow}", priority: 1)
+
+    expect(element.children[initialChildCount].textContent).toBe "a {color: blue}"
+    expect(element.children[initialChildCount + 1].textContent).toBe "a {color: red}"
+    expect(element.children[initialChildCount + 2].textContent).toBe "a {color: yellow}"
+    expect(element.children[initialChildCount + 3].textContent).toBe "a {color: green}"
+
   it "orders style elements by group", ->
     initialChildCount = element.children.length
 

src/style-manager.coffee

@@ -93,6 +93,7 @@ class StyleManager
     sourcePath = params?.sourcePath
     context = params?.context
     group = params?.group
+    priority = params?.priority
 
     if sourcePath? and styleElement = @styleElementsBySourcePath[sourcePath]
       updated = true
@@ -110,6 +111,10 @@ class StyleManager
         styleElement.group = group
         styleElement.setAttribute('group', group)
 
+      if priority?
+        styleElement.priority = priority
+        styleElement.setAttribute('priority', priority)
+
     styleElement.textContent = source
 
     if updated

src/styles-element.coffee

@@ -53,6 +53,7 @@ class StylesElement extends HTMLElement
     styleElementClone = styleElement.cloneNode(true)
     styleElementClone.sourcePath = styleElement.sourcePath
     styleElementClone.context = styleElement.context
+    styleElementClone.priority = styleElement.priority
     @styleElementClonesByOriginalElement.set(styleElement, styleElementClone)
 
     group = styleElement.getAttribute('group')
@@ -62,6 +63,13 @@ class StylesElement extends HTMLElement
           insertBefore = child.nextSibling
           break
 
+    priority = styleElement.priority
+    if priority?
+      for child in @children
+        if child.priority > priority
+          insertBefore = child
+          break
+
     @insertBefore(styleElementClone, insertBefore)
 
     if @context is 'atom-text-editor'