🐛 Fix getTextEditorScrollRatio() return NaN, #260

atom-minimap · Feb 10, 2015 · 2d65659 · 2d65659 · abe33 · Feb 10, 2015
1 parent ebd2509
commit 2d65659
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Showing 2 changed files with 16 additions and 1 deletion.
diff --git a/lib/minimap.coffee b/lib/minimap.coffee
@@ -175,7 +175,8 @@ class Minimap
   #
   # Returns a {Number}.
   getTextEditorScrollRatio: ->
-    @textEditor.getScrollTop() / @getTextEditorMaxScrollTop()
+    # Because `0/0 = NaN`, so make sure that the denominator does not equal `0`.
+    @textEditor.getScrollTop() / (@getTextEditorMaxScrollTop() || 1)
 
   # Returns the `TextEditor` scroll as a value normalized between `0` and `1`.
   #

diff --git a/spec/minimap-spec.coffee b/spec/minimap-spec.coffee
@@ -102,6 +102,20 @@ describe 'Minimap', ->
       editor.setScrollTop(editor.displayBuffer.getMaxScrollTop())
       expect(minimap.getScrollTop()).toEqual(minimap.getMaxScrollTop())
 
+    describe 'when getScrollTop() and maxScrollTop both equal 0', ->
+      beforeEach ->
+        editor.setText(smallSample)
+        editor.setHeight(40)
+        atom.config.set 'editor.scrollPastEnd', true
+
+      it 'getTextEditorScrollRatio() should return 0', ->
+        editor.setScrollTop(0)
+
+        maxScrollTop = editor.displayBuffer.getMaxScrollTop() - (editor.getHeight() - 3 * editor.displayBuffer.getLineHeightInPixels())
+
+        expect(maxScrollTop).toEqual(0)
+        expect(minimap.getTextEditorScrollRatio()).toEqual(0)
+
   describe 'when soft wrap is enabled', ->
     beforeEach ->
       atom.config.set 'editor.softWrap', true