Fix null property access bug in ColorSchemeDropdown

ui/src/shared/components/ColorSchemeDropdown.tsx

@@ -5,7 +5,10 @@ import React, {SFC, CSSProperties} from 'react'
 import {Dropdown, DropdownMenuColors} from 'src/clockface'
 
 // Constants
-import {LINE_COLOR_SCALES} from 'src/shared/constants/graphColorPalettes'
+import {
+  LINE_COLOR_SCALES,
+  DEFAULT_LINE_COLORS,
+} from 'src/shared/constants/graphColorPalettes'
 
 // Styles
 import 'src/shared/components/ColorSchemeDropdown.scss'
@@ -31,7 +34,11 @@ const findSelectedScaleID = (colors: Color[]) => {
   const needle = key(colors)
   const selectedScale = LINE_COLOR_SCALES.find(d => key(d.colors) === needle)
 
-  return selectedScale.id
+  if (selectedScale) {
+    return selectedScale.id
+  } else {
+    return DEFAULT_LINE_COLORS[0].id
+  }
 }
 
 const ColorSchemeDropdown: SFC<Props> = ({value, onChange}) => {

ui/src/shared/components/dygraph/Dygraph.tsx

@@ -224,7 +224,7 @@ class Dygraph extends Component<Props, State> {
 
   private get colors(): string[] {
     const {timeSeries, colors} = this.props
-    const numSeries = get(timeSeries, '0.length', colors.length)
+    const numSeries: number = get(timeSeries, '0.length', colors.length)
     const resolvedColors = getLineColorsHexes(colors, numSeries)
 
     return resolvedColors