fix: factor emptyLineRegexp and whiteSpaceRegexp out of the loop

Author: aminya

lib/mixins/canvas-drawer.js

@@ -401,7 +401,7 @@ export default class CanvasDrawer extends Mixin {
     if (properties.color) { return properties.color }
 
     if (properties.scope) {
-      const scopeString = properties.scope.split(/\s+/)
+      const scopeString = properties.scope.split(whiteSpaceRegexp)
       return this.DOMStylesReader.retrieveStyleFromDom(scopeString, 'background-color', editorElement, true)
     } else {
       return this.getDefaultColor(editorElement)
@@ -605,6 +605,9 @@ export default class CanvasDrawer extends Mixin {
 //    ##     ## ##    ##  ##     ## ##  ##  ##
 //    ########  ##     ## ##     ##  ###  ###
 
+const emptyLineRegexp = /^\s+$/
+const whiteSpaceRegexp = /\s+/
+
 /**
  * Draws a single token on the given context.
  *
@@ -716,7 +719,7 @@ function drawLines (firstRow, lastRow, offsetRow, lineHeight, charHeight, charWi
     }
     if (x > canvasWidth) { return }
 
-    if (/^\s+$/.test(token.text)) {
+    if (emptyLineRegexp.test(token.text)) {
       x += token.text.length * charWidth
     } else {
       x = drawToken(